ADOdb Performance Monitoring Library

### The ADOdb Performance Monitoring Library

v4.991 16 Oct 2008 (c) 2000-2008 John Lim (jlim#natsoft.com)

This software is dual licensed using BSD-Style and LGPL. This means you can use it in compiled proprietary and commercial products.

Useful ADOdb links: Download Other Docs

### Introduction

This module, part of the ADOdb package, provides both CLI and HTML interfaces for viewing key performance indicators of your database. This is very useful because web apps such as the popular phpMyAdmin currently do not provide effective database health monitoring tools. The module provides the following:

- A quick health check of your database server using `$perf->HealthCheck()` or `$perf->HealthCheckCLI()`.
- User interface for performance monitoring, `$perf->UI()`. This UI displays:
  - the health check,
  - all SQL logged and their query plans,
  - a list of all tables in the current database
  - an interface to continiously poll the server for key performance indicators such as CPU, Hit Ratio, Disk I/O
  - a form where you can enter and run SQL interactively.
- Gives you an API to build database monitoring tools for a server farm, for example calling `$perf->DBParameter('data cache hit ratio')` returns this very important statistic in a database independant manner.

ADOdb also has the ability to log all SQL executed, using LogSQL. All SQL logged can be analyzed through the performance monitor UI. In the View SQL mode, we categorize the SQL into 3 types:

- Suspicious SQL: queries with high average execution times, and are potential candidates for rewriting
- Expensive SQL: queries with high total execution times (#executions * avg execution time). Optimizing these queries will reduce your database server load.
- Invalid SQL: queries that generate errors.

Each query is hyperlinked to a description of the query plan, and every PHP script that executed that query is also shown.

Please note that the information presented is a very basic database health check, and does not provide a complete overview of database performance. Although some attempt has been made to make it work across multiple databases in the same way, it is impossible to do so. For the health check, we do try to display the following key database parameters for all drivers:

- data cache size - The amount of memory allocated to the cache.
- data cache hit ratio - A measure of how effective the cache is, as a percentage. The higher, the better.
- current connections - The number of sessions currently connected to the database.

You will need to connect to the database as an administrator to view most of the parameters.

Code improvements as very welcome, particularly adding new database parameters and automated tuning hints.

### Usage

Currently, the following drivers: mysql, postgres, oci8, mssql, informix and db2 are supported. To create a new performance monitor, call NewPerfMonitor( ) as demonstrated below:

    <?php
    include_once('adodb.inc.php');
    session_start(); # session variables required for monitoring
    $conn = ADONewConnection($driver);
    $conn->Connect($server,$user,$pwd,$db);
    $perf =& NewPerfMonitor($conn);
    $perf->UI($pollsecs=5);
    ?>

It is also possible to retrieve a single database parameter:

    $size = $perf->DBParameter('data cache size');

Thx to Fernando Ortiz for the informix module.

### Methods

function UI($pollsecs=5)

Creates a web-based user interface for performance monitoring. When you click on Poll, server statistics will be displayed every $pollsecs seconds. See Usage above.

Since 4.11, we allow users to enter and run SQL interactively via the "Run SQL" link. To disable this for security reasons, set this constant before calling $perf->UI().

    define('ADODB_PERF_NO_RUN_SQL',1);

Sample output follows below:

ADOdb Performance Monitor for localhost, db=test PostgreSQL 7.3.2 on i686-pc-cygwin, compiled by GCC gcc (GCC) 3.2 20020927 (prerelease)
Performance Stats View SQL View Tables Poll Stats

### postgres7
Parameter | Value | Description
Ratios
statistics collector | TRUE | Value must be TRUE to enable hit ratio statistics (stats_start_collector,stats_row_level and stats_block_level must be set to true in postgresql.conf)
data cache hit ratio | 99.7967555299239 |
IO
data reads | 125 |
data writes | 21.78125000000000000 | Count of inserts/updates/deletes * coef
Data Cache
data cache buffers | 640 | Number of cache buffers. Tuning
cache blocksize | 8192 | (estimate)
data cache size | 5M |
operating system cache size | 80M | (effective cache size)
Memory Usage
sort buffer size | 1M | Size of sort buffer (per query)
Connections
current connections | 0 |
max connections | 32 |
Parameters
rollback buffers | 8 | WAL buffers
random page cost | 4 | Cost of doing a seek (default=4). See random_page_cost

function HealthCheck()

Returns database health check parameters as a HTML table. You will need to echo or print the output of this function,

function HealthCheckCLI()

Returns database health check parameters formatted for a command line interface. You will need to echo or print the output of this function. Sample output for mysql:

    -- Ratios --
              MyISAM cache hit ratio => 56.5635738832
              InnoDB cache hit ratio => 0
                 sql cache hit ratio => 0
     -- IO --
                          data reads => 2622
                         data writes => 2415.5
     -- Data Cache --
              MyISAM data cache size => 512K
                 BDB data cache size => 8388600
              InnoDB data cache size => 8M
     -- Memory Pools --
                    read buffer size => 131072
                    sort buffer size => 65528
                         table cache => 4
     -- Connections --
                 current connections => 3
                     max connections => 100

function Poll($pollSecs=5)

Run in infinite loop, displaying the following information every $pollSecs. This will not work properly if output buffering is enabled. In the example below, $pollSecs=3:

    Accumulating statistics...
     Time   WS-CPU%   Hit%   Sess        Reads/s          Writes/s
    11:08:30    0.7  56.56      1         0.0000            0.0000
    11:08:33    1.8  56.56      2         0.0000            0.0000
    11:08:36   11.1  56.55      3         2.5000            0.0000
    11:08:39    9.8  56.55      2         3.1121            0.0000
    11:08:42    2.8  56.55      1         0.0000            0.0000
    11:08:45    7.4  56.55      2         0.0000            1.5000

WS-CPU% is the Web Server CPU load of the server that PHP is running from (eg. the database client), and not the database. The Hit% is the data cache hit ratio. Sess is the current number of sessions connected to the database. If you are using persistent connections, this should not change much. The Reads/s and Writes/s are synthetic values to give the viewer a rough guide to I/O, and are not to be taken literally.

function SuspiciousSQL($numsql=10)

Returns SQL which have high average execution times as a HTML table. Each sql statement is hyperlinked to a new window which details the execution plan and the scripts that execute this SQL.

The number of statements returned is determined by $numsql. Data is taken from the adodb_logsql table, where the sql statements are logged when $connection->LogSQL(true) is enabled. The adodb_logsql table is populated using $conn->LogSQL.

For Oracle, Ixora Suspicious SQL returns a list of SQL statements that are most cache intensive as a HTML table. These are data intensive SQL statements that could benefit most from tuning.

function ExpensiveSQL($numsql=10)

Returns SQL whose total execution time (avg time * #executions) is high as a HTML table. Each sql statement is hyperlinked to a new window which details the execution plan and the scripts that execute this SQL.

The number of statements returned is determined by $numsql. Data is taken from the adodb_logsql table, where the sql statements are logged when $connection->LogSQL(true) is enabled. The adodb_logsql table is populated using $conn->LogSQL.

For Oracle, Ixora Expensive SQL returns a list of SQL statements that are taking the most CPU load when run.

function InvalidSQL($numsql=10)

Returns a list of invalid SQL as an HTML table.

Data is taken from the adodb_logsql table, where the sql statements are logged when $connection->LogSQL(true) is enabled.

function Tables($orderby=1)

Returns information on all tables in a database, with the first two fields containing the table name and table size, the remaining fields depend on the database driver. If $orderby is set to 1, it will sort by name. If $orderby is set to 2, then it will sort by table size. Some database drivers (mssql and mysql) will ignore the $orderby clause. For postgresql, the information is up-to-date since the last vacuum. Not supported currently for db2.

### Raw Functions

Raw functions return values without any formatting.

function DBParameter($paramname)

Returns the value of a database parameter, such as $this->DBParameter("data cache size").

function CPULoad()

Returns the CPU load of the database client (NOT THE SERVER) as a percentage. Only works for Linux and Windows. For Windows, WMI must be available.

### $ADODB_PERF_MIN

New in adodb 4.97/5.03 is this global variable, which controls whether sql timings which are too small are not saved. Currently it defaults to 0.05 (seconds). This means that all sql's which are faster than 0.05 seconds to execute are not saved.

### Format of $settings Property

To create new database parameters, you need to understand $settings. The $settings data structure is an associative array. Each element of the array defines a database parameter. The key is the name of the database parameter. If no key is defined, then it is assumed to be a section break, and the value is the name of the section break. If this is too confusing, looking at the source code will help a lot!

Each database parameter is itself an array consisting of the following elements:

0. Category code, used to group related db parameters. If the category code is 'HIDE', then the database parameter is not shown when HTML() is called.
1. either
   1. sql string to retrieve value, eg. "select value from v\$parameter where name='db_block_size'",
   2. array holding sql string and field to look for, e.g. array('show variables','table_cache'); optional 3rd parameter is the $rs->fields[$index] to use (otherwise $index=1), and optional 4th parameter is a constant to multiply the result with (typically 100 for percentage calculations),
   3. a string prefixed by =, then a PHP method of the class is invoked, e.g. to invoke $this->GetIndexValue(), set this array element to '=GetIndexValue',
2. Description of database parameter. If description begins with an =, then it is interpreted as a method call, just as in (1c) above, taking one parameter, the current value. E.g. '=GetIndexDescription' will invoke $this->GetIndexDescription($val). This is useful for generating tuning suggestions. For an example, see WarnCacheRatio().

Example from MySQL, table_cache database parameter:

    'table cache' => array('CACHE',            # category code
       array("show variables", 'table_cache'), # array (type 1b)
       'Number of tables to keep open'),       # description

### Example Health Check Output

db2 informix mysql mssql oci8 postgres

### db2
Parameter | Value | Description
Ratios
data cache hit ratio | 0 |
Data Cache
data cache buffers | 250 | See tuning reference.
cache blocksize | 4096 |
data cache size | 1000K |
Connections
current connections | 2 |

### informix
Parameter | Val ue | Description
Ratios
data cache hit ratio | 95.89 |
IO
data reads | 1883884 | Page reads
data writes | 1716724 | Page writes
Connections
current connections | 263.0 | Number of sessions

### mysql
Parameter | Value | Description
Ratios
MyISAM cache hit ratio | 56.5658301822 | Cache ratio should be at least 90%
InnoDB cache hit ratio | 0 | Cache ratio should be at least 90%
sql cache hit ratio | 0 |
IO
data reads | 2622 | Number of selects (Key_reads is not accurate)
data writes | 2415.5 | Number of inserts/updates/deletes * coef (Key_writes is not accurate)
Data Cache
MyISAM data cache size | 512K |
BDB data cache size | 8388600 |
InnoDB data cache size | 8M |
Memory Pools
read buffer size | 131072 | (per session)
sort buffer size | 65528 | Size of sort buffer (per session)
table cache | 4 | Number of tables to keep open
Connections
current connections | 3 |
max connections | 100 |

### mssql
Parameter | Value | Description
Ratios
data cache hit ratio | 99.9999694824 |
prepared sql hit ratio | 99.7738579828 |
adhoc sql hit ratio | 98.4540169133 |
IO
data reads | 2858 |
data writes | 1438 |
Data Cache
data cache size | 4362 | in K
Connections
current connections | 14 |
max connections | 32767 |

### oci8
Parameter | Value | Description
Ratios
data cache hit ratio | 96.98 |
sql cache hit ratio | 99.96 |
IO
data reads | 842938 |
data writes | 16852 |
Data Cache
data cache buffers | 3072 | Number of cache buffers
data cache blocksize | 8192 |
data cache size | 48M | shared_pool_size
Memory Pools
java pool size | 0 | java_pool_size
sort buffer size | 512K | sort_area_size (per query)
user session buffer size | 8M | large_pool_size
Connections
current connections | 1 |
max connections | 170 |
data cache utilization ratio | 88.46 | Percentage of data cache actually in use
user cache utilization ratio | 91.76 | Percentage of user cache (large_pool) actually in use
rollback segments | 11 |
Transactions
peak transactions | 24 | Taken from high-water-mark
max transactions | 187 | max transactions / rollback segments < 3.5 (or transactions_per_rollback_segment)
Parameters
cursor sharing | EXACT | Cursor reuse strategy. Recommended is FORCE (8i+) or SIMILAR (9i+). See cursor_sharing.
index cache cost | 0 | % of indexed data blocks expected in the cache. Recommended is 20-80. Default is 0. See optimizer_index_caching.
random page cost | 100 | Recommended is 10-50 for TP, and 50 for data warehouses. Default is 100. See optimizer_index_cost_adj.

### Suspicious SQL

LOAD | EXECUTES | SQL_TEXT
.73% | 89 | select u.name, o.name, t.spare1, t.pctfree$ from sys.obj$ o, sys.user$ u, sys.tab$ t where (bitand(t.trigflag, 1048576) = 1048576) and o.obj#=t.obj# and o.owner# = u.user# select i.obj#, i.flags, u.name, o.name from sys.obj$ o, sys.user$ u, sys.ind$ i where (bitand(i.flags, 256) = 256 or bitand(i.flags, 512) = 512) and (not((i.type# = 9) and bitand(i.flags,8) = 8)) and o.obj#=i.obj# and o.owner# = u.user#
.84% | 3 | select /*+ RULE */ distinct tabs.table_name, tabs.owner , partitioned, iot_type , TEMPORARY, table_type, table_type_owner from DBA_ALL_TABLES tabs where tabs.owner = :own
3.95% | 6 | SELECT round(count(1)*avg(buf.block_size)/1048576) FROM DBA_OBJECTS obj, V$BH bh, dba_segments seg, v$buffer_pool buf WHERE obj.object_id = bh.objd AND obj.owner != 'SYS' and obj.owner = seg.owner and obj.object_name = seg.segment_name and obj.object_type = seg.segment_type and seg.buffer_pool = buf.name and buf.name = 'DEFAULT'
4.50% | 6 | SELECT round(count(1)*avg(tsp.block_size)/1048576) FROM DBA_OBJECTS obj, V$BH bh, dba_segments seg, dba_tablespaces tsp WHERE obj.object_id = bh.objd AND obj.owner != 'SYS' and obj.owner = seg.owner and obj.object_name = seg.segment_name and obj.object_type = seg.segment_type and seg.tablespace_name = tsp.tablespace_name
57.34% | 9267 | select t.schema, t.name, t.flags, q.name from system.aq$_queue_tables t, sys.aq$_queue_table_affinities aft, system.aq$_queues q where aft.table_objno = t.objno and aft.owner_instance = :1 and q.table_objno = t.objno and q.usage = 0 and bitand(t.flags, 4+16+32+64+128+256) = 0 for update of t.name, aft.table_objno skip locked

### Expensive SQL

LOAD | EXECUTES | SQL_TEXT
5.24% | 1 | select round(sum(bytes)/1048576) from dba_segments
6.89% | 6 | SELECT round(count(1)*avg(buf.block_size)/1048576) FROM DBA_OBJECTS obj, V$BH bh, dba_segments seg, v$buffer_pool buf WHERE obj.object_id = bh.objd AND obj.owner != 'SYS' and obj.owner = seg.owner and obj.object_name = seg.segment_name and obj.object_type = seg.segment_type and seg.buffer_pool = buf.name and buf.name = 'DEFAULT'
7.85% | 6 | SELECT round(count(1)*avg(tsp.block_size)/1048576) FROM DBA_OBJECTS obj, V$BH bh, dba_segments seg, dba_tablespaces tsp WHERE obj.object_id = bh.objd AND obj.owner != 'SYS' and obj.owner = seg.owner and obj.object_name = seg.segment_name and obj.object_type = seg.segment_type and seg.tablespace_name = tsp.tablespace_name
33.69% | 89 | select u.name, o.name, t.spare1, t.pctfree$ from sys.obj$ o, sys.user$ u, sys.tab$ t where (bitand(t.trigflag, 1048576) = 1048576) and o.obj#=t.obj# and o.owner# = u.user#
36.44% | 89 | select i.obj#, i.flags, u.name, o.name from sys.obj$ o, sys.user$ u, sys.ind$ i where (bitand(i.flags, 256) = 256 or bitand(i.flags, 512) = 512) and (not((i.type# = 9) and bitand(i.flags,8) = 8)) and o.obj#=i.obj# and o.owner# = u.user#

### postgres7
Parameter | Value | Description
Ratios
statistics collector | FALSE | Must be set to TRUE to enable hit ratio statistics (stats_start_collector,stats_row_level and stats_block_level must be set to true in postgresql.conf)
data cache hit ratio | 99.9666031916603 |
IO
data reads | 15 |
data writes | 0.000000000000000000 | Count of inserts/updates/deletes * coef
Data Cache
data cache buffers | 1280 | Number of cache buffers. Tuning
cache blocksize | 8192 | (estimate)
data cache size | 10M |
operating system cache size | 80000K | (effective cache size)
Memory Pools
sort buffer size | 1M | Size of sort buffer (per query)
Connections
current connections | 13 |
max connections | 32 |
Parameters
rollback buffers | 8 | WAL buffers
random page cost | 4 | Cost of doing a seek (default=4). See random_page_cost