#include <db.h>

int
DB_ENV->txn_stat(DB_ENV *env, DB_TXN_STAT **statp, u_int32_t flags);

Description

The DB_ENV->txn_stat method returns the transaction subsystem statistics.

The flags value must be set to 0 or the following value:

DB_STAT_CLEAR

Reset statistics after returning their values.

The DB_ENV->txn_stat method creates a statistical structure of type DB_TXN_STAT and copies a pointer to it into a user-specified memory location.

Statistical structures are created in allocated memory. If application-specific allocation routines have been declared (see DB_ENV->set_alloc for more information), they are used to allocate the memory; otherwise, the library malloc(3) interface 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_TXN_STAT fields will be filled in:

DB_LSN st_last_ckp;

The LSN of the last checkpoint.

time_t st_time_ckp;

The time the last completed checkpoint finished (as the number of seconds since the Epoch, returned by the IEEE/ANSI Std 1003.1 (POSIX) time interface).

u_int32_t st_last_txnid;

The last transaction ID allocated.

u_int32_t st_maxtxns;

The maximum number of active transactions possible.

u_int32_t st_nactive;

The number of transactions that are currently active.

u_int32_t st_maxnactive;

The maximum number of active transactions at any one time.

u_int32_t st_nbegins;

The number of transactions that have begun.

u_int32_t st_naborts;

The number of transactions that have aborted.

u_int32_t st_ncommits;

The number of transactions that have committed.

u_int32_t st_nrestores;

The number of transactions that have been restored.

u_int32_t st_regsize;

The size of the region.

u_int32_t st_region_wait;

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

u_int32_t st_region_nowait;

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

DB_TXN_ACTIVE *st_txnarray;

A pointer to an array of st_nactive DB_TXN_ACTIVE structures, describing the currently active transactions. The following fields of the DB_TXN_ACTIVE structure will be filled in:

u_int32_t txnid;

The transaction ID of the transaction.

u_int32_t parentid;

The transaction ID of the parent transaction (or 0, if no parent).

DB_LSN lsn;

The current log sequence number when the transaction was begun.

The DB_ENV->txn_stat method returns a non-zero error value on failure and 0 on success.

Errors

The DB_ENV->txn_stat method may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions. If a catastrophic error has occurred, the DB_ENV->txn_stat method may fail and return DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.

Class

See Also