DbEnv.lock_stat
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import com.sleepycat.db.*;
public DbLockStat lock_stat()
throws DbException;
Description
The DbEnv.lock_stat method
creates a DbLockStat object encapsulating a statistical structure.
The lock region statistics are stored in a DbLockStat object.
The following data fields are available from the DbLockStat object:
Statistical structures are created in allocated memory. If db_malloc is non-NULL, it
is called to allocate the memory, otherwise, the library function
malloc(3) is used. The function db_malloc must match
the calling conventions of the malloc(3) library routine.
Regardless, the caller is responsible for deallocating the returned
memory. To deallocate returned memory, free the returned memory
reference, references inside the returned memory do not need to 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:
- public int st_lastid;
- The last allocated lock ID.
- public int st_nmodes;
- The number of lock modes.
- public int st_maxlocks;
- The maximum number of locks possible.
- public int st_nlockers;
- The number of current lockers.
- public int st_maxnlockers;
- The maximum number of lockers at any one time.
- public int st_nrequests;
- The total number of locks requested.
- public int st_nreleases;
- The total number of locks released.
- public int st_nconflicts;
- The total number of locks not immediately available due to conflicts.
- public int st_ndeadlocks;
- The number of deadlocks detected.
- public int st_regsize;
- The size of the region.
- public int st_region_wait;
- The number of times that a thread of control was forced to wait before
obtaining the region lock.
- public int 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 throws an exception that encapsulates a non-zero error value on
failure.
Errors
If a fatal error occurs in Berkeley DB, the DbEnv.lock_stat method will fail and throw a
DbRunRecoveryException, at which point all subsequent database
calls will fail in the same way.
In addition, the DbEnv.lock_stat method may fail and
throw an exception
for errors specified for other Berkeley DB and C library or system methods.
Classes
DbEnv, DbLock
See Also
DbEnv.set_lk_conflicts,
DbEnv.set_lk_detect,
DbEnv.set_lk_max,
DbEnv.lock_detect,
DbEnv.lock_get,
DbEnv.lock_id,
DbLock.put
and
DbEnv.lock_stat.
Copyright Sleepycat Software