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<h2 class="title" style="clear: both"><a id="envset_memory_max"></a>DB_ENV->set_memory_max()</h2>
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<pre class="programlisting">#include <db.h>
int
DB_ENV->set_memory_max(DB_ENV *dbenv, 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="DB_ENV->set_memory_init()">DB_ENV->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">DB_ENV->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="idp60112840"></a>Parameters</h3>
</div>
</div>
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<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp60127648"></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="idp60099512"></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="idp60089280"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">DB_ENV->set_memory_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="idp60138328"></a>EINVAL</h4>
</div>
</div>
</div>
<p>
If the method was called after <a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->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="idp60149408"></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">
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<div>
<h3 class="title"><a id="idp60150744"></a>See Also</h3>
</div>
</div>
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<p>
<a class="xref" href="env.html#envlist" title="Database Environments and Related Methods">Database Environments and Related Methods</a>
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