#include <db_cxx.h>

int
DbEnv::txn_stat(DB_TXN_STAT **statp, u_int32_t flags);

Description: DbEnv::txn_stat

The DbEnv::txn_stat method returns the transaction subsystem statistics.

The DbEnv::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 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_TXN_STAT fields will be filled in:

DbLsn 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 function).

u_int32_t st_last_txnid;

The last transaction ID allocated.

u_int32_t st_maxtxns;

The maximum number of active transactions configured.

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).

DbLsn lsn;

The current log sequence number when the transaction was begun.

u_int32_t xa_status;

If the transaction is an XA transaction, the status of the transaction, otherwise 0.

u_int8_t xid[DB_XIDDATASIZE];

If the transaction is an XA transaction, the transaction's XA ID.

The DbEnv::txn_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::txn_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.

Class

See Also