Berkeley DB: DbEnv.lock_stat
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++

# DbEnv.lock_stat |

`

###

    import com.sleepycat.db.*;

    public DbLockStat lock_stat(int flags)
        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:

The flags value must be set to 0 or the following value:

Db.DB_STAT_CLEAR
  Reset statistics after returning their values.

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_maxlockers;
  The maximum number of lockers possible.
public int st_maxobjects;
  The maximum number of objects possible.
public int st_nlocks;
  The number of current locks.
public int st_maxnlocks;
  The maximum number of locks at any one time.
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_nobjects;
  The number of current objects.
public int st_maxnobjects;
  The maximum number of objects 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_nnowaits;
  The total number of lock requests that failed because Db.DB_LOCK_NOWAIT was set.
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_nlocktimeouts;
  The number of locks that have timed out.
public int 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.
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

The DbEnv.lock_stat method may fail and throw an exception for errors specified for other Berkeley DB and C library or system methods. If a catastrophic error has occurred, the DbEnv.lock_stat method may fail and throw a DbRunRecoveryException, in which case all subsequent Berkeley DB calls will fail in the same way.

# Class

DbEnv, DbLock

# See Also

DbEnv.set_lk_conflicts, DbEnv.set_lk_detect, DbEnv.set_lk_max_lockers, DbEnv.set_lk_max_locks, DbEnv.set_lk_max_objects, DbEnv.lock_detect, DbEnv.lock_get, DbEnv.lock_id, DbEnv.lock_id_free, DbEnv.lock_put, and DbEnv.lock_stat.`

Copyright Sleepycat Software