mirror of
https://github.com/berkeleydb/libdb.git
synced 2024-11-16 17:16:25 +00:00
189 lines
7.8 KiB
HTML
189 lines
7.8 KiB
HTML
<?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->mutex_set_max()</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="mutex.html" title="Chapter 9. Mutex Methods" />
|
||
<link rel="prev" href="mutexset_init.html" title="DB_ENV->mutex_set_init()" />
|
||
<link rel="next" href="mutexset_tas_spins.html" title="DB_ENV->mutex_set_tas_spins()" />
|
||
</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->mutex_set_max()</th>
|
||
</tr>
|
||
<tr>
|
||
<td width="20%" align="left"><a accesskey="p" href="mutexset_init.html">Prev</a> </td>
|
||
<th width="60%" align="center">Chapter 9.
|
||
Mutex Methods
|
||
</th>
|
||
<td width="20%" align="right"> <a accesskey="n" href="mutexset_tas_spins.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="mutexset_max"></a>DB_ENV->mutex_set_max()</h2>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<pre class="programlisting">#include <db.h>
|
||
|
||
int
|
||
DB_ENV->mutex_set_max(DB_ENV *dbenv, u_int32_t max); </pre>
|
||
<p>
|
||
Configure the total number of mutexes to allocate. This method is
|
||
deprecated. The maximum size of the mutex region is now inferred by
|
||
the sizes of the other memory structures, and so this method is no
|
||
longer needed. For example, the cache requires one mutex per page
|
||
in the cache. When you specify the cache size, DB assumes a
|
||
page size of 4K and allocates mutexes accordingly. If your page
|
||
size is different than 4K, you indicate this using
|
||
<a class="xref" href="envset_mp_pagesize.html" title="DB_ENV->set_mp_pagesize()">DB_ENV->set_mp_pagesize()</a>.
|
||
DB will then allocate the proper number of mutexes based on this new page size.
|
||
</p>
|
||
<p>
|
||
You can use this method to override DB's mutex calculation, but
|
||
it is not recommended to do so.
|
||
</p>
|
||
<p>
|
||
Calling the <code class="methodname">DB_ENV->mutex_set_max()</code> method discards any value
|
||
previously set using the
|
||
<a class="xref" href="mutexset_increment.html" title="DB_ENV->mutex_set_increment()">DB_ENV->mutex_set_increment()</a> method.
|
||
</p>
|
||
<p>
|
||
The database environment's total number of mutexes may also be
|
||
configured using the environment's <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file. The syntax of
|
||
the entry in that file is a single line with the string
|
||
"mutex_set_max", one or more whitespace characters, and the total
|
||
number of mutexes. Because the <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is read when the
|
||
database environment is opened, it will silently overrule
|
||
configuration done before that time.
|
||
</p>
|
||
<p>
|
||
The <code class="methodname">DB_ENV->mutex_set_max()</code> method configures a database environment,
|
||
not only operations performed using the specified <a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a> handle.
|
||
</p>
|
||
<p>
|
||
The <code class="methodname">DB_ENV->mutex_set_max()</code> method may not be called after the
|
||
<a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> method is called.
|
||
If the database environment already exists when
|
||
<a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> is called, the
|
||
information specified to <code class="methodname">DB_ENV->mutex_set_max()</code> will be ignored.
|
||
</p>
|
||
<p>
|
||
The <code class="methodname">DB_ENV->mutex_set_max()</code> <span>
|
||
<span>
|
||
method returns a non-zero error value on failure and 0 on success.
|
||
</span>
|
||
|
||
</span>
|
||
</p>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idp61722440"></a>Parameters</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="idp61728072"></a>max</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <span class="bold"><strong>max</strong></span> parameter is the absolute
|
||
number of mutexes to allocate.
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idp61740704"></a>Errors</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <code class="methodname">DB_ENV->mutex_set_max()</code> <span>
|
||
<span>
|
||
method may fail and return one of the following non-zero errors:
|
||
</span>
|
||
|
||
</span>
|
||
</p>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="idp61747784"></a>EINVAL</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
An invalid flag value or parameter was specified.
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idp61746704"></a>Class</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a>
|
||
</p>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idp61745760"></a>See Also</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<a class="xref" href="mutex.html#mutexlist" title="Mutex Methods">Mutex Methods</a>
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="navfooter">
|
||
<hr />
|
||
<table width="100%" summary="Navigation footer">
|
||
<tr>
|
||
<td width="40%" align="left"><a accesskey="p" href="mutexset_init.html">Prev</a> </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="u" href="mutex.html">Up</a>
|
||
</td>
|
||
<td width="40%" align="right"> <a accesskey="n" href="mutexset_tas_spins.html">Next</a></td>
|
||
</tr>
|
||
<tr>
|
||
<td width="40%" align="left" valign="top">DB_ENV->mutex_set_init() </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="h" href="index.html">Home</a>
|
||
</td>
|
||
<td width="40%" align="right" valign="top"> DB_ENV->mutex_set_tas_spins()</td>
|
||
</tr>
|
||
</table>
|
||
</div>
|
||
</body>
|
||
</html>
|