<!--$Id: lock_detect.html,v 1.1.1.1 2003/02/15 04:55:52 zarzycki Exp $--> <!--Copyright 1997-2002 by Sleepycat Software, Inc.--> <!--All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DbEnv.lock_detect</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++"> </head> <body bgcolor=white> <a name="2"><!--meow--></a> <table width="100%"><tr valign=top> <td> <h1>DbEnv.lock_detect</h1> </td> <td align=right> <a href="../api_java/c_index.html"><img src="../images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <hr size=1 noshade> <tt> <h3><pre> import com.sleepycat.db.*; <p> public int lock_detect(int flags, int atype) throws DbException; </pre></h3> <h1>Description</h1> <p>The DbEnv.lock_detect method runs one iteration of the deadlock detector. The deadlock detector traverses the lock table and marks one of the participating lock requesters for rejection in each deadlock it finds. <p>The <b>flags</b> parameter is currently unused, and must be set to 0. <p>The <b>atype</b> parameter specifies which lock request(s) to reject. It must be set to one following list: <p><dl compact> <p><dt><a name="Db.DB_LOCK_DEFAULT">Db.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.DB_LOCK_RANDOM. <dt><a name="Db.DB_LOCK_EXPIRE">Db.DB_LOCK_EXPIRE</a><dd>Reject lock requests which have timed out. No other deadlock detection is performed. <dt><a name="Db.DB_LOCK_MAXLOCKS">Db.DB_LOCK_MAXLOCKS</a><dd>Reject the lock request for the locker ID with the greatest number of locks. <dt><a name="Db.DB_LOCK_MINLOCKS">Db.DB_LOCK_MINLOCKS</a><dd>Reject the lock request for the locker ID with the fewest number of locks. <dt><a name="Db.DB_LOCK_MINWRITE">Db.DB_LOCK_MINWRITE</a><dd>Reject the lock request for the locker ID with the fewest number of write locks. <dt><a name="Db.DB_LOCK_OLDEST">Db.DB_LOCK_OLDEST</a><dd>Reject the lock request for the oldest locker ID. <dt><a name="Db.DB_LOCK_RANDOM">Db.DB_LOCK_RANDOM</a><dd>Reject the lock request for a random locker ID. <dt><a name="Db.DB_LOCK_YOUNGEST">Db.DB_LOCK_YOUNGEST</a><dd>Reject the lock request for the youngest locker ID. </dl> <p>The DbEnv.lock_detect method returns the number of lock requests that were rejected. <p>The DbEnv.lock_detect method throws an exception that encapsulates a non-zero error value on failure. <h1>Errors</h1> <p>The DbEnv.lock_detect method may fail and throw an exception for errors specified for other Berkeley DB and C library or system methods. If a catastrophic error has occurred, the DbEnv.lock_detect method may fail and throw a <a href="../api_java/runrec_class.html">DbRunRecoveryException</a>, in which case all subsequent Berkeley DB calls will fail in the same way. <h1>Class</h1> <a href="../api_java/env_class.html">DbEnv</a>, <a href="../api_java/lock_class.html">DbLock</a> <h1>See Also</h1> <a href="../api_java/lock_list.html">Locking Subsystem and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_java/c_index.html"><img src="../images/api.gif" alt="API"></a><a href="../reftoc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1><a href="http://www.sleepycat.com">Copyright Sleepycat Software</a></font> </body> </html>