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Berkeley DB: lock_stat
lock_stat
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#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
DB_ENV->set_lk_conflicts,
DB_ENV->set_lk_detect,
DB_ENV->set_lk_max,
DB_ENV->set_lk_max_lockers,
DB_ENV->set_lk_max_locks,
DB_ENV->set_lk_max_objects,
lock_detect,
lock_get,
lock_id,
lock_put,
lock_stat,
and
lock_vec.
Copyright Sleepycat Software
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