# DbEnv::set_lk_detect

`

###

    #include <db_cxx.h>

    int
    DbEnv::set_lk_detect(u_int32_t detect);

# 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_LOCK_DEFAULT
  Use the default policy as specified by db_deadlock.
DB_LOCK_OLDEST
  Abort the oldest transaction.
DB_LOCK_RANDOM
  Abort a random transaction involved in the deadlock.
DB_LOCK_YOUNGEST
  Abort the youngest transaction.

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

The DbEnv::set_lk_detect method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success.

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

EINVAL
  An invalid flag value or parameter was specified.

  Called after DbEnv::open was called.

### Classes

DbEnv, DbLock

# See Also

DbEnv::set_lk_conflicts, DbEnv::set_lk_detect, DbEnv::set_lk_max_locks, DbEnv::set_lk_max_lockers, DbEnv::set_lk_max_objects, DbEnv::set_lk_max, DbEnv::lock_detect, DbEnv::lock_get, DbEnv::lock_id, DbLock::put, DbEnv::lock_stat and DbEnv::lock_vec.`

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