#include <db_cxx.h>

int
DbEnv::lock_stat(DB_LOCK_STAT **statp, u_int32_t flags);

Description: DbEnv::lock_stat

The DbEnv::lock_stat method returns the locking subsystem statistics.

The DbEnv::lock_stat method creates a statistical structure of type DB_LOCK_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_LOCK_STAT fields will be filled in:

u_int32_t st_id;

The last allocated locker ID.

u_int32_t st_cur_maxid;

The current maximum unused locker ID.

u_int32_t st_nmodes;

The number of lock modes.

u_int32_t st_maxlocks;

The maximum number of locks possible.

u_int32_t st_maxlockers;

The maximum number of lockers possible.

u_int32_t st_maxobjects;

The maximum number of lock objects possible.

u_int32_t st_nlocks;

The number of current locks.

u_int32_t st_maxnlocks;

The maximum number of locks at any one time.

u_int32_t st_nlockers;

The number of current lockers.

u_int32_t st_maxnlockers;

The maximum number of lockers at any one time.

u_int32_t st_nobjects;

The number of current lock objects.

u_int32_t st_maxnobjects;

The maximum number of lock objects at any one time.

u_int32_t st_nrequests;

The total number of locks requested.

u_int32_t st_nreleases;

The total number of locks released.

u_int32_t st_nnowaits;

The total number of lock requests failing because DB_LOCK_NOWAIT was set.

u_int32_t st_nconflicts;

The total number of locks not immediately available due to conflicts.

u_int32_t st_ndeadlocks;

The number of deadlocks.

u_int32_t st_locktimeout;

Lock timeout value.

u_int32_t st_nlocktimeouts;

The number of lock requests that have timed out.

u_int32_t st_txntimeout;

Transaction timeout value.

u_int32_t st_ntxntimeouts;

The number of transactions that have timed out. This value is also a component of st_ndeadlocks, the total number of deadlocks detected.

u_int32_t st_regsize;

The size of the lock 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.

The DbEnv::lock_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::lock_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