Berkeley DB: DbEnv::log_stat
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++

DbEnv::log_stat |

`

    #include <db_cxx.h>

    int
    DbEnv::log_stat(DB_LOG_STAT **statp, u_int32_t flags);

    int
    DbEnv::log_stat_print(u_int32_t flags);

Description: DbEnv::log_stat

The DbEnv::log_stat method returns the logging subsystem statistics.

The DbEnv::log_stat method creates a statistical structure of type DB_LOG_STAT and copies a pointer to it into a user-specified memory location.

Statistical structures are stored in allocated memory. If application-specific allocation routines have been declared (see DbEnv::set_alloc for more information), they are used to allocate the memory; otherwise, the standard C library malloc(3) is used. The caller is responsible for deallocating the memory. To deallocate the memory, free the memory reference; references inside the returned memory need not be individually freed.

The following DB_LOG_STAT fields will be filled in:

u_int32_t st_magic;

- The magic number that identifies a file as a log file.

u_int32_t st_version;

- The version of the log file type.

int st_mode;

- The mode of any created log files.

u_int32_t st_lg_bsize;

- The in-memory log record cache size.

u_int32_t st_lg_size;

- The log file size.

u_int32_t st_record;

- The number of records written to this log.

u_int32_t st_w_mbytes;

- The number of megabytes written to this log.

u_int32_t st_w_bytes;

- The number of bytes over and above st_w_mbytes written to this log.

u_int32_t st_wc_mbytes;

- The number of megabytes written to this log since the last checkpoint.

u_int32_t st_wc_bytes;

- The number of bytes over and above st_wc_mbytes written to this log since the last checkpoint.

u_int32_t st_wcount;

- The number of times the log has been written to disk.

u_int32_t st_wcount_fill;

- The number of times the log has been written to disk because the in-memory log record cache filled up.

u_int32_t st_rcount;

- The number of times the log has been read from disk.

u_int32_t st_scount;

- The number of times the log has been flushed to disk.

u_int32_t st_cur_file;

- The current log file number.

u_int32_t st_cur_offset;

- The byte offset in the current log file.

u_int32_t st_disk_file;

- The log file number of the last record known to be on disk.

u_int32_t st_disk_offset;

- The byte offset of the last record known to be on disk.

u_int32_t st_maxcommitperflush;

- The maximum number of commits contained in a single log flush.

u_int32_t st_mincommitperflush;

- The minimum number of commits contained in a single log flush that contained a commit.

roff_t st_regsize;

- The size of the log region, in bytes.

u_int32_t st_region_wait;

- The number of times that a thread of control was forced to wait before obtaining the log region mutex.

u_int32_t st_region_nowait;

- The number of times that a thread of control was able to obtain the log region mutex without waiting.

The DbEnv::log_stat method may not be called before the DbEnv::open method is called.

The DbEnv::log_stat method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success.

Parameters
flags

- The flags parameter must be set to 0 or the following value:
  DB_STAT_CLEAR
  - Reset statistics after returning their values.

statp

- The statp parameter references memory into which a pointer to the allocated statistics structure is copied.

Errors

The DbEnv::log_stat method may fail and throw DbException, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:

EINVAL

- An invalid flag value or parameter was specified.

Description: DbEnv::log_stat_print

The DbEnv::log_stat_print method displays the logging subsystem statistical information, as described for the DbEnv::log_stat method. The information is printed to a specified output channel (see the DbEnv::set_msgfile method for more information), or passed to an application callback function (see the DbEnv::set_msgcall method for more information).

The DbEnv::log_stat_print method may not be called before the DbEnv::open method is called.

The DbEnv::log_stat_print method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success.

Parameters
flags

- The flags parameter must be set to 0 or by bitwise inclusively OR'ing together one or more of the following values:
  DB_STAT_ALL
  - Display all available information.
  DB_STAT_CLEAR
  - Reset statistics after displaying their values.

Class DbEnv, DbLogc, DbLsn
See Also Logging Subsystem and Related Methods`

Copyright (c) 1996,2008 Oracle. All rights reserved.