#include <db.h>

int
lock_stat(DB_ENV *env, DB_LOCK_STAT **statp);

Description

The lock_stat function creates a statistical structure 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 function 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 lock region statistics are stored in a structure of type DB_LOCK_STAT. The following DB_LOCK_STAT fields will be filled in:

u_int32_t st_lastid;

The last allocated lock 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 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 objects.

u_int32_t st_maxnobjects;

The maximum number of 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 that failed 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 detected.

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.

The lock_stat function returns a non-zero error value on failure and 0 on success.

Errors

The lock_stat function 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 lock_stat function may fail and return DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.

See Also