1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
<?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_metadata_dir.html" title="DbEnv::set_metadata_dir()" />
</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">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_metadata_dir.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(u_int32_t gbytes, u_int32_t bytes); </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="idp7531776"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp7531968"></a>gbytes</h4>
</div>
</div>
</div>
<p>
The maximum memory is set to
<span class="bold"><strong>gbytes</strong></span> gigabytes plus
<span class="bold"><strong>bytes</strong></span>.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp7501072"></a>bytes</h4>
</div>
</div>
</div>
<p>
The maximum memory is set to
<span class="bold"><strong>gbytes</strong></span> gigabytes plus
<span class="bold"><strong>bytes</strong></span>.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp7472600"></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="idp7536432"></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="idp7473960"></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="idp7515344"></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_metadata_dir.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_metadata_dir()</td>
</tr>
</table>
</div>
</body>
</html>
|
