<!--$Id: memp_sync.html,v 1.2 2004/03/30 01:21:42 jtownsen Exp $--> <!--Copyright 1997-2003 by Sleepycat Software, Inc.--> <!--All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DB_ENV->memp_sync</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> <h3>DB_ENV->memp_sync</h3> </td> <td align=right> <a href="../api_c/api_index.html"><img src="../images/api.gif" alt="API"></a> <a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <hr size=1 noshade> <tt> <h3><pre> #include <db.h> <p> int DB_ENV->memp_sync(DB_ENV *env, DB_LSN *lsn); </pre></h3> <hr size=1 noshade> <h3>Description: DB_ENV->memp_sync</h3> <p>The DB_ENV->memp_sync method flushes modified pages in the cache to their backing files.</p> <p>Pages in the pool that cannot be immediately written back to disk (for example, pages that are currently in use by another thread of control) are waited for and written to disk as soon as it is possible to do so.</p> <p>To support the DB_ENV->memp_sync functionality, it is necessary that the pool functions know the location of the log sequence number on the page for each file type. This location should be specified when the file is opened using the <a href="../api_c/memp_set_lsn_offset.html">DB_MPOOLFILE->set_lsn_offset</a> method. It is not required that the log sequence number be aligned on the page in any way.</p> <p>The DB_ENV->memp_sync method returns a non-zero error value on failure and 0 on success. </p> <h3>Parameters</h3> <p><dl compact> <p><dt><b>lsn</b><dd> The purpose of the <b>lsn</b> parameter is to enable a transaction manager to ensure, as part of a checkpoint, that all pages modified by a certain time have been written to disk. <p>All modified pages with a a log sequence number (<a href="../api_c/lsn_class.html">DB_LSN</a>) less than the <b>lsn</b> parameter are written to disk. If <b>lsn</b> is NULL, all modified pages in the pool are written to disk.</p> </dl> <h3>Errors</h3> <p>The DB_ENV->memp_sync method may fail and return one of the following non-zero errors:</p> <p><dl compact> <p><dt>EINVAL<dd>If the DB_ENV->memp_sync function was called without logging having been initialized in the environment; or if an invalid flag value or parameter was specified. </dl> <hr size=1 noshade> <h3>Class</h3> <a href="../api_c/env_class.html">DB_ENV</a>, <a href="../api_c/mempfile_class.html">DB_MPOOLFILE</a> <h3>See Also</h3> <a href="../api_c/memp_list.html">Memory Pools and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_c/api_index.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1><a href="../sleepycat/legal.html">Copyright (c) 1996-2003</a> <a href="http://www.sleepycat.com">Sleepycat Software, Inc.</a> - All rights reserved.</font> </body> </html>