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>DbEnv::txn_checkpoint()</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="txn.html" title="Chapter 13. The DbTxn Handle" /> 11 <link rel="prev" href="txnbegin.html" title="DbEnv::txn_begin()" /> 12 <link rel="next" href="txncommit.html" title="DbTxn::commit()" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">DbEnv::txn_checkpoint()</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="txnbegin.html">Prev</a> </td> 22 <th width="60%" align="center">Chapter 13. 23 The DbTxn Handle 24 </th> 25 <td width="20%" align="right"> <a accesskey="n" href="txncommit.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="txncheckpoint"></a>DbEnv::txn_checkpoint()</h2> 35 </div> 36 </div> 37 </div> 38 <pre class="programlisting">#include <db_cxx.h> 39 40int 41DbEnv::txn_checkpoint(u_int32_t kbyte, u_int32_t min, u_int32_t flags) const;</pre> 42 <p> 43 If there has been any logging activity in the database environment 44 since the last checkpoint, the <code class="methodname">DbEnv::txn_checkpoint()</code> method 45 flushes the underlying memory pool, writes a checkpoint record to the 46 log, and then flushes the log. 47 </p> 48 <p> 49 The <code class="methodname">DbEnv::txn_checkpoint()</code> method returns a non-zero error value on 50 failure and 0 on success. 51 </p> 52 <p> 53 The <code class="methodname">DbEnv::txn_checkpoint()</code> method is the underlying method used by 54 the <a class="link" href="db_checkpoint.html" title="db_checkpoint">db_checkpoint</a> 55 utility. See the <a class="link" href="db_checkpoint.html" title="db_checkpoint">db_checkpoint</a> utility 56 source code for an example of using <code class="methodname">DbEnv::txn_checkpoint()</code> in a 57 IEEE/ANSI Std 1003.1 (POSIX) environment. 58 </p> 59 <div class="sect2" lang="en" xml:lang="en"> 60 <div class="titlepage"> 61 <div> 62 <div> 63 <h3 class="title"><a id="id1713916"></a>Parameters</h3> 64 </div> 65 </div> 66 </div> 67 <div class="sect3" lang="en" xml:lang="en"> 68 <div class="titlepage"> 69 <div> 70 <div> 71 <h4 class="title"><a id="id1713572"></a>flags</h4> 72 </div> 73 </div> 74 </div> 75 <p> 76 The <span class="bold"><strong>flags</strong></span> parameter must be set to 0 77 or the following value: 78 </p> 79 <div class="itemizedlist"> 80 <ul type="disc"> 81 <li> 82 <p> 83 <code class="literal">DB_FORCE</code> 84 </p> 85 <p> 86 Force a checkpoint record, even if there has been no activity since 87 the last checkpoint. 88 </p> 89 </li> 90 </ul> 91 </div> 92 </div> 93 <div class="sect3" lang="en" xml:lang="en"> 94 <div class="titlepage"> 95 <div> 96 <div> 97 <h4 class="title"><a id="id1714256"></a>kbyte</h4> 98 </div> 99 </div> 100 </div> 101 <p> 102 If the <span class="bold"><strong>kbyte</strong></span> parameter is non-zero, a 103 checkpoint will be done if more than <span class="bold"><strong>kbyte</strong></span> kilobytes of log data have been written 104 since the last checkpoint. 105 </p> 106 </div> 107 <div class="sect3" lang="en" xml:lang="en"> 108 <div class="titlepage"> 109 <div> 110 <div> 111 <h4 class="title"><a id="id1714393"></a>min</h4> 112 </div> 113 </div> 114 </div> 115 <p> 116 If the <span class="bold"><strong>min</strong></span> parameter is non-zero, a 117 checkpoint will be done if more than <span class="bold"><strong>min</strong></span> minutes have passed since the last 118 checkpoint. 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="id1714245"></a>Errors</h3> 127 </div> 128 </div> 129 </div> 130 <p> 131 The <code class="methodname">DbEnv::txn_checkpoint()</code> <span> 132 133 <span> 134 method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a> 135 exception, encapsulating one of the following non-zero errors, or return one 136 of the following non-zero errors: 137 </span> 138 </span> 139 </p> 140 <div class="sect3" lang="en" xml:lang="en"> 141 <div class="titlepage"> 142 <div> 143 <div> 144 <h4 class="title"><a id="id1713834"></a>EINVAL</h4> 145 </div> 146 </div> 147 </div> 148 <p> 149 An invalid flag value or parameter was specified. 150 </p> 151 </div> 152 </div> 153 <div class="sect2" lang="en" xml:lang="en"> 154 <div class="titlepage"> 155 <div> 156 <div> 157 <h3 class="title"><a id="id1714181"></a>Class</h3> 158 </div> 159 </div> 160 </div> 161 <p> 162 <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>, <a class="link" href="txn.html" title="Chapter 13. The DbTxn Handle">DbTxn</a> 163 </p> 164 </div> 165 <div class="sect2" lang="en" xml:lang="en"> 166 <div class="titlepage"> 167 <div> 168 <div> 169 <h3 class="title"><a id="id1714170"></a>See Also</h3> 170 </div> 171 </div> 172 </div> 173 <p> 174 <a class="xref" href="txn.html#txnlist" title="Transaction Subsystem and Related Methods">Transaction Subsystem and Related Methods</a> 175 </p> 176 </div> 177 </div> 178 <div class="navfooter"> 179 <hr /> 180 <table width="100%" summary="Navigation footer"> 181 <tr> 182 <td width="40%" align="left"><a accesskey="p" href="txnbegin.html">Prev</a> </td> 183 <td width="20%" align="center"> 184 <a accesskey="u" href="txn.html">Up</a> 185 </td> 186 <td width="40%" align="right"> <a accesskey="n" href="txncommit.html">Next</a></td> 187 </tr> 188 <tr> 189 <td width="40%" align="left" valign="top">DbEnv::txn_begin() </td> 190 <td width="20%" align="center"> 191 <a accesskey="h" href="index.html">Home</a> 192 </td> 193 <td width="40%" align="right" valign="top"> DbTxn::commit()</td> 194 </tr> 195 </table> 196 </div> 197 </body> 198</html> 199