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.\" Manual Page for Berkely DB utils, created from upstream
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.\" documentation by Thijs Kinkhorst <thijs@kinkhorst.com>.
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.TH DB5.2_DEADLOCK 1 "28 January 2005"
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db5.2_deadlock \- Detect and abort deadlocks
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[-Vv] [-a e | m | n | o | W | w | y] [-h home] [-L file] [-t sec.usec]
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The db5.2_deadlock utility traverses the database environment lock region, and
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aborts a lock request each time it detects a deadlock or a lock request that
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has timed out. By default, in the case of a deadlock, a random lock request is
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This utility should be run as a background daemon, or the underlying Berkeley
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DB deadlock detection interfaces should be called in some other way, whenever
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there are multiple threads or processes accessing a database and at least one
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of them is modifying it.
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When a deadlock is detected, abort the locker:
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with the most write locks
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with the fewest write locks
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with the youngest lock
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When lock or transaction timeouts have been specified:
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abort any lock request that has timed out
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Specify a home directory for the database environment; by
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default, the current working directory is used.
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Log the execution of the db5.2_deadlock utility to the specified file in the
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following format, where \fI###\fR is the process ID, and the date
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is the time the utility was started.
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db_deadlock: ### Wed Jun 15 01:23:45 EDT 1995
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This file will be removed if the db5.2_deadlock utility exits gracefully.
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Check the database environment every \fBsec\fR seconds plus
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\fBusec\fR microseconds to see if a process has been forced to wait
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for a lock; if one has, review the database environment lock
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Write the library version number to the standard output, and exit.
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Run in verbose mode, generating messages each time the detector runs.
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If the \fB-t\fR option is not specified, db5.2_deadlock will
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The db5.2_deadlock utility uses a Berkeley DB environment (as described for the
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\fB-h\fR option, the environment variable \fBDB_HOME\fR, or
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because the utility was run in a directory containing a Berkeley DB
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environment). In order to avoid environment corruption when using a
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Berkeley DB environment, db5.2_deadlock should always be given the chance to
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detach from the environment and exit gracefully. To cause db5.2_deadlock
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to release all environment resources and exit cleanly, send it an
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interrupt signal (SIGINT).
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The db5.2_deadlock utility does not attempt to create the Berkeley DB
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shared memory regions if they do not already exist. The application
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which creates the region should be started first, and then, once the
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region is created, the db5.2_deadlock utility should be started.
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The DB_ENV->lock_detect method is the underlying method used by the
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db_deadlock utility. See the db_deadlock utility source code for an
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example of using DB_ENV->lock_detect
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in a IEEE/ANSI Std 1003.1 (POSIX) environment.
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The db5.2_deadlock utility exits 0 on success, and >0 if an error occurs.
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If the \fB-h\fR option is not specified and the environment variable
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DB_HOME is set, it is used as the path of the database home, as described
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Sleepycat Software, Inc. This manual page was created based on
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the HTML documentation for db_deadlock from Sleepycat,
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by Thijs Kinkhorst <thijs@kinkhorst.com>,
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for the Debian system (but may be used by others).
added
removed
debian/manpages/db5.2_deadlock.1
