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 |

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    import com.sleepycat.db.*;

    public DbLockStat lock_stat(int flags)
        throws DbException;

# Description

The DbEnv.lock_stat method returns the locking subsystem statistics.

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

Db.DB_STAT_CLEAR
  Reset statistics after returning their values.

The DbEnv.lock_stat method creates a DbLockStat object encapsulating the lock region statistics. The following data fields are available from the DbLockStat object:

public int st_id;
  The last allocated locker ID.
public int st_cur_maxid;
  The current maximum unused locker 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 lock 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 lock objects.
public int st_maxnobjects;
  The maximum number of lock 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 failing 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.
public int st_locktimeout;
  Lock timeout value.
public int st_nlocktimeouts;
  The number of locks that have timed out.
public int st_txntimeout;
  Transaction timeout value.
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 lock 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

Locking Subsystem and Related Methods`

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