Berkeley DB: DbEnv.set_lk_detect
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.set_lk_detect |

`

###

    import com.sleepycat.db.*;

    public void set_lk_detect(int detect)
    	throws DbException;

# Description

Set if the deadlock detector is to be run whenever a lock conflict occurs, and specify which transaction should be aborted in the case of a deadlock. The specified value must be one of the following list:

Db.DB_LOCK_DEFAULT
  Use the default policy as specified by db_deadlock.
Db.DB_LOCK_MAXLOCKS
  Abort the transaction with the greatest number of locks.
Db.DB_LOCK_MINLOCKS
  Abort the transaction with the fewest locks.
Db.DB_LOCK_MINWRITE
  Abort the transaction with the fewest write locks.
Db.DB_LOCK_OLDEST
  Abort the oldest transaction.
Db.DB_LOCK_RANDOM
  Abort a random transaction involved in the deadlock.
Db.DB_LOCK_YOUNGEST
  Abort the youngest transaction.

The DbEnv.set_lk_detect interface may be used only to configure Berkeley DB before the DbEnv.open interface is called.

The DbEnv.set_lk_detect method throws an exception that encapsulates a non-zero error value on failure.

The database environment's deadlock detector configuration may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lk_detect", one or more whitespace characters, and the interface detect argument as a string; for example, "set_lk_detect DB_LOCK_OLDEST". Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

# Errors

The DbEnv.set_lk_detect method may fail and throw an exception encapsulating a non-zero error for the following conditions:

EINVAL
  An invalid flag value or parameter was specified.

  Called after DbEnv.open was called.

The DbEnv.set_lk_detect 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.set_lk_detect 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, DbEnv.set_lk_max_lockers, DbEnv.set_lk_max_locks, DbEnv.set_lk_max_objects, DbEnv.lock_detect, DbEnv.lock_get, DbEnv.lock_id, DbLock.put, and DbEnv.lock_stat.`

Copyright Sleepycat Software