mirror of
https://github.com/berkeleydb/libdb.git
synced 2024-11-17 01:26:25 +00:00
183 lines
7.5 KiB
HTML
183 lines
7.5 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>DbEnv::set_memory_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="env.html" title="Chapter 5. The DbEnv Handle" />
|
||
<link rel="prev" href="envset_memory_init.html" title="DbEnv::set_memory_init()" />
|
||
<link rel="next" href="envset_message_stream.html" title="DbEnv::set_message_stream()" />
|
||
</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_memory_max()</th>
|
||
</tr>
|
||
<tr>
|
||
<td width="20%" align="left"><a accesskey="p" href="envset_memory_init.html">Prev</a> </td>
|
||
<th width="60%" align="center">Chapter 5.
|
||
The DbEnv Handle
|
||
</th>
|
||
<td width="20%" align="right"> <a accesskey="n" href="envset_message_stream.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_memory_max"></a>DbEnv::set_memory_max()</h2>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<pre class="programlisting">#include <db_cxx.h>
|
||
|
||
int
|
||
DbEnv::set_memory_max(roff_t size); </pre>
|
||
<p>
|
||
This method sets the maximum amount of memory to be used by shared
|
||
structures in the main environment region. These are the
|
||
structures used to coordinate access to the environment other than
|
||
mutexes and those in the page cache (memory pool). If the region
|
||
files are in memory mapped files, or if
|
||
<code class="literal">DB_PRIVATE</code> is specified, the memory specified by
|
||
this method is not allocated completely at startup. As memory is
|
||
needed, the shared region will be extended or, in the case of
|
||
<code class="literal">DB_PRIVATE</code>, more memory will be allocated using
|
||
the system malloc call. For memory mapped files, a mapped region
|
||
will be allocated to this size but the underlying file will only be
|
||
allocated sufficient memory to hold the initial allocation of
|
||
shared memory structures as set by
|
||
<a class="xref" href="envset_memory_init.html" title="DbEnv::set_memory_init()">DbEnv::set_memory_init()</a>.
|
||
</p>
|
||
<p>
|
||
If no memory maximum is specified then it is calculated from
|
||
defaults, initial settings or (deprecated) maximum settings of the
|
||
various shared structures. In the case of environments created
|
||
with <code class="literal">DB_PRIVATE</code>, no maximum need be set and the
|
||
shared structure allocation will grow as needed until the process
|
||
memory limit is exhausted.
|
||
</p>
|
||
<p>
|
||
The database environment's maximum memory 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 "set_memory_max", one or more whitespace characters,
|
||
followed by the maximum to be allocated. 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">DbEnv::set_memory_max()</code> method must be
|
||
called prior to opening the database environment.
|
||
</p>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3624960"></a>Parameters</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="id3624461"></a>size</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <span class="bold"><strong>size</strong></span> parameter
|
||
identifies the maximum number of bytes to allocate.
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3625379"></a>Errors</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The <code class="methodname">DbEnv::set_memory_max()</code> <span>
|
||
|
||
<span>
|
||
method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
|
||
exception, encapsulating one of the following non-zero errors, or 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="id3625568"></a>EINVAL</h4>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
If the method was called after <a class="xref" href="envopen.html" title="DbEnv::open()">DbEnv::open()</a>
|
||
was called; or if 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="id3625510"></a>Class</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>
|
||
</p>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="id3624733"></a>See Also</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
<a class="xref" href="env.html#envlist" title="Database Environments and Related Methods">Database Environments and Related 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="envset_memory_init.html">Prev</a> </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="u" href="env.html">Up</a>
|
||
</td>
|
||
<td width="40%" align="right"> <a accesskey="n" href="envset_message_stream.html">Next</a></td>
|
||
</tr>
|
||
<tr>
|
||
<td width="40%" align="left" valign="top">DbEnv::set_memory_init() </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="h" href="index.html">Home</a>
|
||
</td>
|
||
<td width="40%" align="right" valign="top"> DbEnv::set_message_stream()</td>
|
||
</tr>
|
||
</table>
|
||
</div>
|
||
</body>
|
||
</html>
|