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195 lines
7.9 KiB
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<title>DbEnv::set_cache_max()</title>
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<p>Library Version 11.2.5.2</p>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">DbEnv::set_cache_max()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="memptrickle.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 9.
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The DbMpoolFile Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="envset_cachesize.html">Next</a></td>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="envset_cache_max"></a>DbEnv::set_cache_max()</h2>
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</div>
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</div>
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</div>
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<pre class="programlisting">#include <db_cxx.h>
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int
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DbEnv::set_cache_max(u_int32_t gbytes, u_int32_t bytes); </pre>
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<p>
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Sets the maximum cache size in bytes. The specified size is
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rounded to the nearest multiple of the cache region size, which is
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the initial cache size divided by the number of regions specified
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to the <a class="xref" href="envset_cachesize.html" title="DbEnv::set_cachesize()">DbEnv::set_cachesize()</a> method. If no value is
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specified, it defaults to the initial cache
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size.
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</p>
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<p>
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The database environment's maximum cache size may also be
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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
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the entry in that file is a single line with the string
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"set_cache_max", one or more whitespace characters, and the
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maximum cache size in bytes, specified in two parts: the gigabytes
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of cache and the additional bytes of cache. Because the
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<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,
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it will silently overrule configuration done before that time.
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</p>
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<p>
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The <code class="methodname">DbEnv::set_cache_max()</code> method configures a database environment,
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not only operations performed using the specified
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<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> handle.
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</p>
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<p>
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The <code class="methodname">DbEnv::set_cache_max()</code> method may be called at any time during
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the life of the application.
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</p>
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<p>
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The <code class="methodname">DbEnv::set_cache_max()</code> <span>
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<span>
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method either returns a non-zero error value or throws an
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exception that encapsulates a non-zero error value on
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failure, and returns 0 on success.
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</span>
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</span>
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</p>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3646219"></a>Parameters</h3>
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</div>
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</div>
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</div>
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<div class="sect3" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h4 class="title"><a id="id3646208"></a>gbytes</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>gbytes</strong></span> parameter specifies the number of
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bytes which, when added to the <span class="bold"><strong>bytes</strong></span>
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parameter, specifies the maximum size of the cache.
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</p>
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</div>
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<div class="sect3" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h4 class="title"><a id="id3645968"></a>bytes</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>bytes</strong></span> parameter specifies the number of
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bytes which, when added to the <span class="bold"><strong>gbytes</strong></span>
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parameter, specifies the maximum size of the cache.
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</p>
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</div>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3646110"></a>Errors</h3>
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</div>
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</div>
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</div>
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<p>
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The <code class="methodname">DbEnv::set_cache_max()</code> <span>
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<span>
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method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
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exception, encapsulating one of the following non-zero errors, or return one
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of the following non-zero errors:
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</span>
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</span>
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</p>
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<div class="sect3" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h4 class="title"><a id="id3646369"></a>EINVAL</h4>
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</div>
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</div>
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</div>
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<p>
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An invalid flag value or parameter was specified.
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</p>
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</div>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3646354"></a>Class</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>
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</p>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3646083"></a>See Also</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="xref" href="env.html#envlist" title="Database Environments and Related Methods">Database Environments and Related Methods</a>
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</p>
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</div>
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</div>
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<div class="navfooter">
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<hr />
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<table width="100%" summary="Navigation footer">
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<tr>
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<td width="40%" align="left"><a accesskey="p" href="memptrickle.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="memp.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="envset_cachesize.html">Next</a></td>
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</tr>
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<tr>
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<td width="40%" align="left" valign="top">DbEnv::memp_trickle() </td>
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<td width="20%" align="center">
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<a accesskey="h" href="index.html">Home</a>
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</td>
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<td width="40%" align="right" valign="top"> DbEnv::set_cachesize()</td>
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</tr>
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</table>
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</body>
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</html>
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