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<!--$Id: lockng.so,v 1.6 2004/09/28 14:13:09 bostic Exp $--> <!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB Reference Guide: Release 4.2: DB_LOCK_NOTGRANTED</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> </head> <body bgcolor=white> <table width="100%"><tr valign=top> <td><b><dl><dt>Berkeley DB Reference Guide:<dd>Upgrading Berkeley DB Applications</dl></b></td> <td align=right><a href="../upgrade.4.2/verify.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../upgrade.4.2/repinit.html"><img src="../../images/next.gif" alt="Next"></a> </td></tr></table> <p align=center><b>Release 4.2: DB_LOCK_NOTGRANTED</b></p> <p>In previous releases, configuring lock or transaction timeout values or calling the <a href="../../api_c/txn_begin.html">DB_ENV->txn_begin</a> method with the <a href="../../api_c/txn_begin.html#DB_TXN_NOWAIT">DB_TXN_NOWAIT</a> flag caused database operation methods to return <a href="../../ref/program/errorret.html#DB_LOCK_NOTGRANTED">DB_LOCK_NOTGRANTED</a>, or throw a <a href="../../api_cxx/lockng_class.html">DbLockNotGrantedException</a> exception. This required applications to unnecessarily handle multiple errors or exception types.</p> <p>In the Berkeley DB 4.2 release, with one exception, database operations will no longer return <a href="../../ref/program/errorret.html#DB_LOCK_NOTGRANTED">DB_LOCK_NOTGRANTED</a> or throw a <a href="../../api_cxx/lockng_class.html">DbLockNotGrantedException</a> exception. Instead, database operations will return <a href="../../ref/program/errorret.html#DB_LOCK_DEADLOCK">DB_LOCK_DEADLOCK</a> or throw a <a href="../../api_cxx/deadlock_class.html">DbDeadlockException</a> exception. This change should require no application changes, as applications must already be dealing with the possible <a href="../../ref/program/errorret.html#DB_LOCK_DEADLOCK">DB_LOCK_DEADLOCK</a> error return or <a href="../../api_cxx/deadlock_class.html">DbDeadlockException</a> exception from database operations.</p> <p>The one exception to this rule is the <a href="../../api_c/db_get.html">DB->get</a> method using the <a href="../../api_c/db_get.html#DB_CONSUME_WAIT">DB_CONSUME_WAIT</a> flag to consume records from a Queue. If lock or transaction timeouts are set, this method and flag combination may return <a href="../../ref/program/errorret.html#DB_LOCK_NOTGRANTED">DB_LOCK_NOTGRANTED</a> or throw a <a href="../../api_cxx/lockng_class.html">DbLockNotGrantedException</a> exception.</p> <p>Applications wanting to distinguish between true deadlocks and timeouts can configure database operation methods to return <a href="../../ref/program/errorret.html#DB_LOCK_NOTGRANTED">DB_LOCK_NOTGRANTED</a> or throw a <a href="../../api_cxx/lockng_class.html">DbLockNotGrantedException</a> exception using the <a href="../../api_c/env_set_flags.html#DB_TIME_NOTGRANTED">DB_TIME_NOTGRANTED</a> flag.</p> <p>The <a href="../../api_c/lock_get.html">DB_ENV->lock_get</a> and <a href="../../api_c/lock_vec.html">DB_ENV->lock_vec</a> methods will continue to return <a href="../../ref/program/errorret.html#DB_LOCK_NOTGRANTED">DB_LOCK_NOTGRANTED</a>, or throw a <a href="../../api_cxx/lockng_class.html">DbLockNotGrantedException</a> exception as they have previously done.</p> <table width="100%"><tr><td><br></td><td align=right><a href="../upgrade.4.2/verify.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../upgrade.4.2/repinit.html"><img src="../../images/next.gif" alt="Next"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> </body> </html>
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