NAME

       db5.3_deadlock - Detect and abort deadlocks

SYNOPSIS

       db5.3_deadlock [-Vv] [-a e | m | n | o | W | w | y] [-h home] [-L file] [-t sec.usec]

DESCRIPTION

       The db5.3_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     Specify  a  home directory for the database environment; by default, the current working directory
              is used.

       -L     Log the execution of the db5.3_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 db5.3_deadlock utility exits gracefully.

       -t      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 structures.

       -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, db5.3_deadlock will run once and exit.

       The db5.3_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  environment,
       db5.3_deadlock  should always be given the chance to detach from the environment and exit gracefully.  To
       cause db5.3_deadlock to release all environment resources and exit cleanly, send it an  interrupt  signal
       (SIGINT).

       The  db5.3_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 db5.3_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.

       The db5.3_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.

AUTHORS

       Sleepycat Software, Inc. This manual page was created based on the  HTML  documentation  for  db_deadlock
       from  Sleepycat,  by  Thijs  Kinkhorst  <thijs@kinkhorst.com>,  for the Debian system (but may be used by
       others).

                                                 28 January 2005                               DB5.3_DEADLOCK(1)