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4.2 KiB
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<!--$Id: db_deadlock.so,v 10.22 2000/11/29 16:52:38 bostic Exp $-->
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<!--Copyright 1997, 1998, 1999, 2000 by Sleepycat Software, Inc.-->
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<!--All rights reserved.-->
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<html>
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<head>
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<title>Berkeley DB: db_deadlock</title>
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<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
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<meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++">
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</head>
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<body bgcolor=white>
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<a name="2"><!--meow--></a>
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<table><tr valign=top>
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<td>
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<h1>db_deadlock</h1>
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</td>
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<td width="1%">
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<a href="../api_c/c_index.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a>
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</td></tr></table>
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<hr size=1 noshade>
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<tt>
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<h3><pre>db_deadlock [<b>-Vvw</b>]
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[<b>-a o | y</b>] [<b>-h home</b>] [<b>-L file</b>] [<b>-t sec</b>]</pre></h3>
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<h1>Description</h1>
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<a name="3"><!--meow--></a>
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<p>The db_deadlock utility traverses the database lock structures
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and aborts a lock request each time it detects a deadlock. By default,
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a random lock request is chosen to be aborted. This utility should be
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run as a background daemon, or the underlying Berkeley DB deadlock detection
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interfaces should be called in some other way, whenever there are
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multiple threads or processes accessing a database and at least one of
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them is modifying it.
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<p>The options are as follows:
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<p><dl compact>
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<p><dt><b>-a</b><dd>When a deadlock is detected, abort the oldest (o) lock request or the
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youngest (y) lock request.
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<p><dt><b>-h</b><dd>Specify a home directory for the database environment; by
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default, the current working directory is used.
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<p><dt><b>-L</b><dd>Log the execution of the db_deadlock utility to the specified file in the
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following format, where <i>###</i> is the process ID, and the date
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is the time the utility was started.
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<p><blockquote><pre>db_deadlock: ### Wed Jun 15 01:23:45 EDT 1995</pre></blockquote>
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This file will be removed if the db_deadlock utility exits gracefully.
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<p><dt><b>-t</b><dd>Initiate a pass over the database locks at least every <b>sec</b>
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seconds.
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<p><dt><b>-V</b><dd>Write the version number to the standard output and exit.
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<p><dt><b>-v</b><dd>Run in verbose mode, generating messages each time the detector runs.
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<p><dt><b>-w</b><dd>Make a single pass over the database locks every time a process is
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forced to wait for a lock.
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</dl>
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<p>At least one of the <b>-t</b> and <b>-w</b> options must be specified.
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<p>The db_deadlock utility uses a Berkeley DB environment (as described for the
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<b>-h</b> option, the environment variable <b>DB_HOME</b>, 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 Berkeley DB
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environment, db_deadlock should always be given the chance to detach from
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the environment and exit gracefully. To cause db_deadlock to release all
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environment resources and exit cleanly, send it an interrupt signal
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(SIGINT).
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<p>The db_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 db_deadlock utility should be started.
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<p>The db_deadlock utility exits 0 on success, and >0 if an error occurs.
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<h1>Environment Variables</h1>
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<p><dl compact>
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<p><dt>DB_HOME<dd>If the <b>-h</b> 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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in <a href="../api_c/env_open.html">DBENV->open</a>.
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</dl>
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<h1>See Also</h1>
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<a href="../utility/berkeley_db_svc.html">berkeley_db_svc</a>,
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<a href="../utility/db_archive.html">db_archive</a>,
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<a href="../utility/db_checkpoint.html">db_checkpoint</a>,
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db_deadlock,
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<a href="../utility/db_dump.html">db_dump</a>,
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<a href="../utility/db_load.html">db_load</a>,
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<a href="../utility/db_recover.html">db_recover</a>,
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<a href="../utility/db_stat.html">db_stat</a>,
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<a href="../utility/db_upgrade.html">db_upgrade</a>,
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and
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<a href="../utility/db_verify.html">db_verify</a>.
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</tt>
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<p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font>
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</body>
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</html>
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