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DB_DEADLOCK(1)               BerkeleyDB Utilities               DB_DEADLOCK(1)
NAME
       db_deadlock - Detect deadlocks and abort lock requests
SYNOPSIS
       db_deadlock  [-Vv]  [-a e | m | n | o | W | w | y ] [-h home] [-L file]
       [-t sec.usec]
DESCRIPTION
       The db_deadlock utility traverses the database environment lock region,
       and  aborts  a  lock  request each time it detects a deadlock or a lock
       request that has timed out. By default, in the case of  a  deadlock,  a
       random lock request is chosen to be aborted.
       This  utility  should  be run as a background daemon, or the underlying
       Berkeley DB deadlock detection interfaces  should  be  called  in  some
       other way, whenever there are multiple threads or processes accessing a
       database and at least one of them is modifying it.
OPTIONS
       -a     When a deadlock is detected, abort the locker:
              m      with the most locks
              n      with the fewest locks
              o      with the oldest lock
              W      with the most write locks
              w      with the fewest write locks
              y      with the youngest lock
              When lock or transaction timeouts have been specified:
              e      abort any lock request that has timed out
       -h home
              Specify a  home  directory  for  the  database  environment;  by
              default, the current working directory is used.
       -L file
              Log  the  execution  of the db_deadlock utility to the specified
              file in the following format, where ### is the process  ID,  and
              the date is the time the utility was started.
              db_deadlock: ### Wed Jun 15 01:23:45 EDT 1995
              This  file  will  be  removed  if  the db_deadlock utility exits
              gracefully.
       -t sec.usec
              Check the database  environment  every  sec  seconds  plus  usec
              microseconds  to  see if a process has been forced to wait for a
              lock; if one has, review the database  environment  lock  struc-
              tures.
       -V     Write  the  library  version  number to the standard output, and
              exit.
       -v     Run in verbose mode, generating messages each time the  detector
              runs.
       If the -t option is not specified, db_deadlock will run once and exit.
       The  db_deadlock  utility  uses a Berkeley DB environment (as described
       for the -h option, the environment variable  DB_HOME,  or  because  the
       utility  was  run in a directory containing a Berkeley DB environment).
       In order to avoid environment corruption when using a Berkeley DB envi-
       ronment,  db_deadlock  should always be given the chance to detach from
       the environment and exit gracefully.  To cause db_deadlock  to  release
       all environment resources and exit cleanly, send it an interrupt signal
       (SIGINT).
       The db_deadlock utility does not attempt  to  create  the  Berkeley  DB
       shared  memory  regions  if they do not already exist.  The application
       which creates the region should be started first, and  then,  once  the
       region is created, the db_deadlock utility should be started.
       The  DB_ENV->lock_detect  method  is  the underlying method used by the
       db_deadlock utility. See the db_deadlock utility  source  code  for  an
       example  of using DB_ENV->lock_detect in a IEEE/ANSI Std 1003.1 (POSIX)
       environment.
EXIT STATUS
       The db_deadlock utility exits 0 on success, and >0 if an error occurs.
ENVIRONMENT
       DB_HOME
              If the -h option is not specified and the  environment  variable
              DB_HOME  is set, it is used as the path of the database home, as
              described in DB_ENV->open.
SEE ALSO
       db_archive(1) db_checkpoint(1) db_dump(1)  db_hotbackup(1)  db_log_ver-
       ify(1)    db_load(1)   db_printlog(1)   db_recover(1)   db_replicate(1)
       db_stat(1) db_tuner(1) db_upgrade(1) db_verify(1)
BerkeleyDB 5.3.28              06 December 2016                 DB_DEADLOCK(1)