<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>DB_ENV->set_mp_mtxcount()</title> <link rel="stylesheet" href="apiReference.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> <link rel="start" href="index.html" title="Berkeley DB C API Reference" /> <link rel="up" href="memp.html" title="Chapter 8. The DB_MPOOLFILE Handle" /> <link rel="prev" href="envset_mp_mmapsize.html" title="DB_ENV->set_mp_mmapsize()" /> <link rel="next" href="envset_mp_pagesize.html" title="DB_ENV->set_mp_pagesize()" /> </head> <body> <div xmlns="" class="navheader"> <div class="libver"> <p>Library Version 11.2.5.3</p> </div> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">DB_ENV->set_mp_mtxcount()</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="envset_mp_mmapsize.html">Prev</a> </td> <th width="60%" align="center">Chapter 8. The DB_MPOOLFILE Handle </th> <td width="20%" align="right"> <a accesskey="n" href="envset_mp_pagesize.html">Next</a></td> </tr> </table> <hr /> </div> <div class="sect1" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h2 class="title" style="clear: both"><a id="envset_mp_mtxcount"></a>DB_ENV->set_mp_mtxcount()</h2> </div> </div> </div> <pre class="programlisting">#include <db.h> int DB_ENV->set_mp_mtxcount(DB_ENV *dbenv, u_int32_t mtxcount); </pre> <p> The <code class="methodname">DB_ENV->set_mp_mtxcount()</code> method overrides the default number of mutexes for the hash table in each memory pool cache. The defualt is one mutex per hash bucket. Setting it to a lower number decreases the number of mutexes used and the amount of memory needed to store them at the expense of concurrency in the memory pool. This can also improve startup time. Setting a number greater than the number size of the hash table will waste mutexes and space. </p> <p> You must call this method only before the environment is opened. </p> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp53376176"></a>Parameters</h3> </div> </div> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp53382232"></a>mtxcount</h4> </div> </div> </div> <p> Specifies the number of mutexes allocated to the buffer pool hash table. </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp53382728"></a>Class</h3> </div> </div> </div> <p> <a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a>, <a class="link" href="memp.html" title="Chapter 8. The DB_MPOOLFILE Handle">DB_MPOOLFILE</a> </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp53396056"></a>See Also</h3> </div> </div> </div> <p> <a class="xref" href="memp.html#memplist" title="Memory Pools and Related Methods">Memory Pools and Related Methods</a>, <a class="xref" href="envget_mp_mtxcount.html" title="DB_ENV->get_mp_mtxcount()">DB_ENV->get_mp_mtxcount()</a> </p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="envset_mp_mmapsize.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="memp.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="envset_mp_pagesize.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">DB_ENV->set_mp_mmapsize() </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> DB_ENV->set_mp_pagesize()</td> </tr> </table> </div> </body> </html>