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172 lines
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<title>DbEnv::set_mp_max_openfd()</title>
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<p>Library Version 11.2.5.2</p>
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<tr>
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<th colspan="3" align="center">DbEnv::set_mp_max_openfd()</th>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="envset_cachesize.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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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="mempset_mp_max_openfd"></a>DbEnv::set_mp_max_openfd()</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_mp_max_openfd(int maxopenfd); </pre>
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<p>
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The <code class="methodname">DbEnv::set_mp_max_openfd()</code> method limits the number of file
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descriptors the library will open concurrently when flushing dirty
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pages from the cache.
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</p>
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<p>
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The database environment's limit on open file descriptors to flush
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dirty pages may also be configured using the environment's
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<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
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line with the string "set_mp_max_openfd", one or more whitespace
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characters, and the number of open file descriptors. 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 <a class="xref" href="mempset_mp_max_openfd.html" title="DbEnv::set_mp_max_openfd()">DbEnv::set_mp_max_openfd()</a>
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method configures a database environment, not only operations
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performed using the specified <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_mp_max_openfd()</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="id3646767"></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="id3646756"></a>maxopenfd</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 maximum number of file descriptors that may be concurrently opened
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by the library when flushing dirty pages from 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="id3646660"></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_mp_max_openfd()</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="id3646840"></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="id3646819"></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>, <a class="link" href="memp.html" title="Chapter 9. The DbMpoolFile Handle">DbMpoolFile</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="id3646753"></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="memp.html#memplist" title="Memory Pools and Related Methods">Memory Pools 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="envset_cachesize.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="mempset_mp_max_write.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::set_cachesize() </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_mp_max_write()</td>
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</tr>
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