1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>DB_ENV->set_mp_max_openfd()</title> 7 <link rel="stylesheet" href="apiReference.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Berkeley DB C API Reference" /> 10 <link rel="up" href="memp.html" title="Chapter 8. The DB_MPOOLFILE Handle" /> 11 <link rel="prev" href="envset_cachesize.html" title="DB_ENV->set_cachesize()" /> 12 <link rel="next" href="mempset_mp_max_write.html" title="DB_ENV->set_mp_max_write()" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">DB_ENV->set_mp_max_openfd()</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="envset_cachesize.html">Prev</a> </td> 22 <th width="60%" align="center">Chapter 8. 23 The DB_MPOOLFILE Handle 24 </th> 25 <td width="20%" align="right"> <a accesskey="n" href="mempset_mp_max_write.html">Next</a></td> 26 </tr> 27 </table> 28 <hr /> 29 </div> 30 <div class="sect1" lang="en" xml:lang="en"> 31 <div class="titlepage"> 32 <div> 33 <div> 34 <h2 class="title" style="clear: both"><a id="mempset_mp_max_openfd"></a>DB_ENV->set_mp_max_openfd()</h2> 35 </div> 36 </div> 37 </div> 38 <pre class="programlisting">#include <db.h> 39 40int 41DB_ENV->set_mp_max_openfd(DB_ENV *env, int maxopenfd); </pre> 42 <p> 43 The <code class="methodname">DB_ENV->set_mp_max_openfd()</code> method limits the number of file 44 descriptors the library will open concurrently when flushing dirty 45 pages from the cache. 46 </p> 47 <p> 48 The database environment's limit on open file descriptors to flush 49 dirty pages may also be configured using the environment's 50 <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file. The 51 syntax of the entry in that file is a single line with the string 52 "set_max_openfd", one or more whitespace characters, and the number of 53 open file descriptors. Because the 54 <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is 55 read when the database environment is opened, it will silently 56 overrule configuration done before that time. 57 </p> 58 <p> 59 The <a class="xref" href="mempset_mp_max_openfd.html" title="DB_ENV->set_mp_max_openfd()">DB_ENV->set_mp_max_openfd()</a> 60 method configures a database environment, not only operations 61 performed using the specified <a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a> handle. 62 </p> 63 <p> 64 The <code class="methodname">DB_ENV->set_mp_max_openfd()</code> <span> 65 <span> 66 method returns a non-zero error value on failure and 0 on success. 67 </span> 68 69 </span> 70 </p> 71 <div class="sect2" lang="en" xml:lang="en"> 72 <div class="titlepage"> 73 <div> 74 <div> 75 <h3 class="title"><a id="id1688634"></a>Parameters</h3> 76 </div> 77 </div> 78 </div> 79 <div class="sect3" lang="en" xml:lang="en"> 80 <div class="titlepage"> 81 <div> 82 <div> 83 <h4 class="title"><a id="id1688645"></a>maxopenfd</h4> 84 </div> 85 </div> 86 </div> 87 <p> 88 The maximum number of file descriptors that may be concurrently opened 89 by the library when flushing dirty pages from the cache. 90 </p> 91 </div> 92 </div> 93 <div class="sect2" lang="en" xml:lang="en"> 94 <div class="titlepage"> 95 <div> 96 <div> 97 <h3 class="title"><a id="id1688808"></a>Errors</h3> 98 </div> 99 </div> 100 </div> 101 <p> 102 The <code class="methodname">DB_ENV->set_mp_max_openfd()</code> <span> 103 <span> 104 method may fail and return one of the following non-zero errors: 105 </span> 106 107 </span> 108 </p> 109 <div class="sect3" lang="en" xml:lang="en"> 110 <div class="titlepage"> 111 <div> 112 <div> 113 <h4 class="title"><a id="id1688713"></a>EINVAL</h4> 114 </div> 115 </div> 116 </div> 117 <p> 118 An invalid flag value or parameter was specified. 119 </p> 120 </div> 121 </div> 122 <div class="sect2" lang="en" xml:lang="en"> 123 <div class="titlepage"> 124 <div> 125 <div> 126 <h3 class="title"><a id="id1687837"></a>Class</h3> 127 </div> 128 </div> 129 </div> 130 <p> 131 <a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a>, <a class="link" href="memp.html" title="Chapter 8. The DB_MPOOLFILE Handle">DB_MPOOLFILE</a> 132 </p> 133 </div> 134 <div class="sect2" lang="en" xml:lang="en"> 135 <div class="titlepage"> 136 <div> 137 <div> 138 <h3 class="title"><a id="id1688570"></a>See Also</h3> 139 </div> 140 </div> 141 </div> 142 <p> 143 <a class="xref" href="memp.html#memplist" title="Memory Pools and Related Methods">Memory Pools and Related Methods</a> 144 </p> 145 </div> 146 </div> 147 <div class="navfooter"> 148 <hr /> 149 <table width="100%" summary="Navigation footer"> 150 <tr> 151 <td width="40%" align="left"><a accesskey="p" href="envset_cachesize.html">Prev</a> </td> 152 <td width="20%" align="center"> 153 <a accesskey="u" href="memp.html">Up</a> 154 </td> 155 <td width="40%" align="right"> <a accesskey="n" href="mempset_mp_max_write.html">Next</a></td> 156 </tr> 157 <tr> 158 <td width="40%" align="left" valign="top">DB_ENV->set_cachesize() </td> 159 <td width="20%" align="center"> 160 <a accesskey="h" href="index.html">Home</a> 161 </td> 162 <td width="40%" align="right" valign="top"> DB_ENV->set_mp_max_write()</td> 163 </tr> 164 </table> 165 </div> 166 </body> 167</html> 168