libdb/docs/api_reference/CXX/envset_mp_mtxcount.html

128 lines
4.9 KiB
HTML
Raw Normal View History

2011-09-13 17:44:24 +00:00
<?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>DbEnv::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 9.  The DbMpoolFile Handle" />
<link rel="prev" href="envset_mp_mmapsize.html" title="DbEnv::set_mp_mmapsize()" />
<link rel="next" href="envset_mp_pagesize.html" title="DbEnv::set_mp_pagesize()" />
</head>
<body>
<div xmlns="" class="navheader">
<div class="libver">
<p>Library Version 11.2.5.2</p>
</div>
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">DbEnv::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 9. 
The DbMpoolFile 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>DbEnv::set_mp_mtxcount()</h2>
</div>
</div>
</div>
<pre class="programlisting">#include &lt;db_cxx.h&gt;
int
DbEnv::set_mp_mtxcount(u_int32_t mtxcount);</pre>
<p>
The <code class="methodname">DbEnv::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>
2011-12-20 00:07:10 +00:00
<h3 class="title"><a id="id3627654"></a>Parameters</h3>
2011-09-13 17:44:24 +00:00
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
2011-12-20 00:07:10 +00:00
<h4 class="title"><a id="id3627658"></a>mtxcount</h4>
2011-09-13 17:44:24 +00:00
</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>
2011-12-20 00:07:10 +00:00
<h3 class="title"><a id="id3627916"></a>Class</h3>
2011-09-13 17:44:24 +00:00
</div>
</div>
</div>
<p>
<a class="link" href="env.html" title="Chapter 5.  The DbEnv Handle">DbEnv</a>,
<a class="link" href="memp.html" title="Chapter 9.  The DbMpoolFile Handle">DbMpoolFile</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
2011-12-20 00:07:10 +00:00
<h3 class="title"><a id="id3627934"></a>See Also</h3>
2011-09-13 17:44:24 +00:00
</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="DbEnv::get_mp_mtxcount()">DbEnv::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">DbEnv::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"> DbEnv::set_mp_pagesize()</td>
</tr>
</table>
</div>
</body>
</html>