<!--$Id: env_set_lk_detect.so,v 10.50 2006/02/27 14:51:30 bostic Exp $--> <!--Copyright (c) 1997,2007 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DB_ENV->set_lk_detect</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> <h3>DB_ENV->set_lk_detect</h3> </td> <td align=right> <a href="../../db46-devel-4.6.21/api_c/api_core.html"><img src="../../db46-devel-4.6.21/images/api.gif" alt="API"></a> <a href="../../db46-devel-4.6.21/ref/toc.html"><img src="../../db46-devel-4.6.21/images/ref.gif" alt="Ref"></a></td> </tr></table> <hr size=1 noshade> <tt> <h3><pre> #include <db.h> <p> int DB_ENV->set_lk_detect(DB_ENV *dbenv, u_int32_t detect); <p> int DB_ENV->get_lk_detect(DB_ENV *dbenv, u_int32_t *lk_detectp); </pre></h3> <hr size=1 noshade> <h3>Description: DB_ENV->set_lk_detect</h3> <p>Set if the deadlock detector is to be run whenever a lock conflict occurs, and specify what lock request(s) should be rejected. As transactions acquire locks on behalf of a single locker ID, rejecting a lock request associated with a transaction normally requires the transaction be aborted.</p> <p>The database environment's deadlock detector configuration may also be configured using the environment's <b>DB_CONFIG</b> file. The syntax of the entry in that file is a single line with the string "set_lk_detect", one or more whitespace characters, and the method <b>detect</b> parameter as a string; for example, "set_lk_detect DB_LOCK_OLDEST". Because the <b>DB_CONFIG</b> file is read when the database environment is opened, it will silently overrule configuration done before that time.</p> <p>The DB_ENV->set_lk_detect method configures a database environment, not only operations performed using the specified <a href="../../db46-devel-4.6.21/api_c/env_class.html">DB_ENV</a> handle.</p> <p>The DB_ENV->set_lk_detect method may be called at any time during the life of the application.</p> <p>The DB_ENV->set_lk_detect method returns a non-zero error value on failure and 0 on success. </p> <h3>Parameters</h3> <dl compact> <dt><b>detect</b><dd>The <b>detect</b> parameter configures the deadlock detector. The specified value must be one of the following list: <dl compact> <dt><a name="DB_LOCK_DEFAULT">DB_LOCK_DEFAULT</a><dd>Use whatever lock policy was specified when the database environment was created. If no lock policy has yet been specified, set the lock policy to DB_LOCK_RANDOM. <dt><a name="DB_LOCK_EXPIRE">DB_LOCK_EXPIRE</a><dd>Reject lock requests which have timed out. No other deadlock detection is performed. <dt><a name="DB_LOCK_MAXLOCKS">DB_LOCK_MAXLOCKS</a><dd>Reject the lock request for the locker ID with the most locks. <dt><a name="DB_LOCK_MAXWRITE">DB_LOCK_MAXWRITE</a><dd>Reject the lock request for the locker ID with the most write locks. <dt><a name="DB_LOCK_MINLOCKS">DB_LOCK_MINLOCKS</a><dd>Reject the lock request for the locker ID with the fewest locks. <dt><a name="DB_LOCK_MINWRITE">DB_LOCK_MINWRITE</a><dd>Reject the lock request for the locker ID with the fewest write locks. <dt><a name="DB_LOCK_OLDEST">DB_LOCK_OLDEST</a><dd>Reject the lock request for the locker ID with the oldest lock. <dt><a name="DB_LOCK_RANDOM">DB_LOCK_RANDOM</a><dd>Reject the lock request for a random locker ID. <dt><a name="DB_LOCK_YOUNGEST">DB_LOCK_YOUNGEST</a><dd>Reject the lock request for the locker ID with the youngest lock. </dl> </dl> <h3>Errors</h3> <p>The DB_ENV->set_lk_detect method may fail and return one of the following non-zero errors:</p> <dl compact> <dt>EINVAL<dd>An invalid flag value or parameter was specified. </dl> <hr size=1 noshade> <h3>Description: DB_ENV->get_lk_detect</h3> <p>The DB_ENV->get_lk_detect method returns the deadlock detector configuration.</p> <p>The DB_ENV->get_lk_detect method may be called at any time during the life of the application.</p> <p>The DB_ENV->get_lk_detect method returns a non-zero error value on failure and 0 on success. </p> <h3>Parameters</h3> <dl compact> <dt><b>lk_detectp</b><dd>The DB_ENV->get_lk_detect method returns the deadlock detector configuration in <b>lk_detectp</b>. </dl> <hr size=1 noshade> <h3>Class</h3> <a href="../../db46-devel-4.6.21/api_c/env_class.html">DB_ENV</a>, <a href="../../db46-devel-4.6.21/api_c/lock_class.html">DB_LOCK</a> <h3>See Also</h3> <a href="../../db46-devel-4.6.21/api_c/lock_list.html">Locking Subsystem and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../../db46-devel-4.6.21/api_c/api_core.html"><img src="../../db46-devel-4.6.21/images/api.gif" alt="API"></a><a href="../../db46-devel-4.6.21/ref/toc.html"><img src="../../db46-devel-4.6.21/images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2007 Oracle. 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