<!--$Id: env_set_lk_detect.so,v 10.50 2006/02/27 14:51:30 bostic Exp $--> <!--Copyright (c) 1997,2008 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> <b>DB_ENV->set_lk_detect</b> </td> <td align=right> <a href="../../db47-devel-4.7.25/api_c/api_core.html"><img src="../../db47-devel-4.7.25/images/api.gif" alt="API"></a> <a href="../../db47-devel-4.7.25/ref/toc.html"><img src="../../db47-devel-4.7.25/images/ref.gif" alt="Ref"></a></td> </tr></table> <hr size=1 noshade> <tt> <b><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></b> <hr size=1 noshade> <b>Description: DB_ENV->set_lk_detect</b> <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 <a href="../../db47-devel-4.7.25/ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> 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 <a href="../../db47-devel-4.7.25/ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> 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="../../db47-devel-4.7.25/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> <b>Parameters</b> <br> <b>detect</b><ul compact><li>The <b>detect</b> parameter configures the deadlock detector. The specified value must be one of the following list: <br> <b><a name="DB_LOCK_DEFAULT">DB_LOCK_DEFAULT</a></b><ul compact><li>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.</ul> <b><a name="DB_LOCK_EXPIRE">DB_LOCK_EXPIRE</a></b><ul compact><li>Reject lock requests which have timed out. No other deadlock detection is performed.</ul> <b><a name="DB_LOCK_MAXLOCKS">DB_LOCK_MAXLOCKS</a></b><ul compact><li>Reject the lock request for the locker ID with the most locks.</ul> <b><a name="DB_LOCK_MAXWRITE">DB_LOCK_MAXWRITE</a></b><ul compact><li>Reject the lock request for the locker ID with the most write locks.</ul> <b><a name="DB_LOCK_MINLOCKS">DB_LOCK_MINLOCKS</a></b><ul compact><li>Reject the lock request for the locker ID with the fewest locks.</ul> <b><a name="DB_LOCK_MINWRITE">DB_LOCK_MINWRITE</a></b><ul compact><li>Reject the lock request for the locker ID with the fewest write locks.</ul> <b><a name="DB_LOCK_OLDEST">DB_LOCK_OLDEST</a></b><ul compact><li>Reject the lock request for the locker ID with the oldest lock.</ul> <b><a name="DB_LOCK_RANDOM">DB_LOCK_RANDOM</a></b><ul compact><li>Reject the lock request for a random locker ID.</ul> <b><a name="DB_LOCK_YOUNGEST">DB_LOCK_YOUNGEST</a></b><ul compact><li>Reject the lock request for the locker ID with the youngest lock.</ul> <br></ul> <br> <br><b>Errors</b> <p>The DB_ENV->set_lk_detect method may fail and return one of the following non-zero errors:</p> <br> <b>EINVAL</b><ul compact><li>An invalid flag value or parameter was specified.</ul> <br> <hr size=1 noshade> <b>Description: DB_ENV->get_lk_detect</b> <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> <b>Parameters</b> <br> <b>lk_detectp</b><ul compact><li>The DB_ENV->get_lk_detect method returns the deadlock detector configuration in <b>lk_detectp</b>.</ul> <br> <hr size=1 noshade> <br><b>Class</b> <a href="../../db47-devel-4.7.25/api_c/env_class.html">DB_ENV</a>, <a href="../../db47-devel-4.7.25/api_c/lock_class.html">DB_LOCK</a> <br><b>See Also</b> <a href="../../db47-devel-4.7.25/api_c/lock_list.html">Locking Subsystem and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../../db47-devel-4.7.25/api_c/api_core.html"><img src="../../db47-devel-4.7.25/images/api.gif" alt="API"></a><a href="../../db47-devel-4.7.25/ref/toc.html"><img src="../../db47-devel-4.7.25/images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2008 Oracle. 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