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223 lines
9.3 KiB
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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<title>DB_ENV->set_backup_config()</title>
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Berkeley DB C API Reference" />
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<link rel="up" href="env.html" title="Chapter 5. The DB_ENV Handle" />
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<link rel="prev" href="envset_backup_callbacks.html" title="DB_ENV->set_backup_callbacks()" />
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<body>
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<div xmlns="" class="navheader">
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<p>Library Version 11.2.5.3</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">DB_ENV->set_backup_config()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="envset_backup_callbacks.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 5.
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The DB_ENV Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="envset_data_dir.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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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_backup_config"></a>DB_ENV->set_backup_config()</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.h>
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DB_ENV->set_backup_config(DB_ENV, db_backup_config_t option,
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u_int32_t value); </pre>
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<p>
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The <code class="methodname">DB_ENV->set_backup_config()</code> method
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configures tuning parameters for the hot backup APIs. See the
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<a class="xref" href="envbackup.html" title="DB_ENV->backup()">DB_ENV->backup()</a>
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and
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<a class="xref" href="envdbbackup.html" title="DB_ENV->dbbackup()">DB_ENV->dbbackup()</a>
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methods for a description of the hot backup APIs.
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</p>
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<p>
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The <code class="methodname">DB_ENV->set_backup_config()</code> method
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configures operations performed using the specified
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<a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a> handle, not all operations
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performed on the underlying database environment.
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</p>
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<p>
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The <code class="methodname">DB_ENV->set_backup_config()</code> method may
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be called at any time during the life of the application.
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</p>
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<p>
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The <code class="methodname">DB_ENV->set_backup_config()</code> <span>
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<span>
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method returns a non-zero error value on failure and 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="idp59829624"></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="idp59833704"></a>option</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>option</strong></span> parameter
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identifies the backup parameter to be modified. It
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must be one of the following:
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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<p>
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<code class="literal">DB_BACKUP_WRITE_DIRECT</code>
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</p>
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<p>
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Turning this on causes direct I/O to be used when
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writing pages to the disk. For some environments,
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direct I/O can provide faster write throughput, but
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usually it is slower because the OS buffer pool
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offers asynchronous activity.
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</p>
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<p>
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By default, this option is turned off.
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</p>
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</li>
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<li>
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<p>
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<code class="literal">DB_BACKUP_READ_COUNT</code>
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</p>
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<p>
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Configures the number of pages to read before
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pausing. Increasing this value increases the amount
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of I/O the backup process performs for any given
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time interval. If your application is already
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heavily I/O bound, setting this value to a lower
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number may help to improve your overall data
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throughput by reducing the I/O demands placed on
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your system.
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</p>
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<p>
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By default, all pages are read without a pause.
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</p>
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</li>
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<li>
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<p>
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<code class="literal">DB_BACKUP_READ_SLEEP</code>
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</p>
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<p>
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Configures the number of microseconds to sleep
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between batches of reads. Increasing this value
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decreases the amount of I/O the backup process
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performs for any given time interval. If your
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application is already heavily I/O bound, setting
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this value to a higher number may help to improve
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your overall data throughput by reducing the I/O
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demands placed on your system.
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</p>
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</li>
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<li>
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<p>
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<code class="literal">DB_BACKUP_SIZE</code>
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</p>
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<p>
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Configures the size of the buffer, in bytes, to
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read from the database. Default is 1 megabyte.
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</p>
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</li>
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</ul>
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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="idp59842384"></a>value</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>value</strong></span> parameter sets
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the configuration value for the option identified by the
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<span class="bold"><strong>option</strong></span> parameter. For
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those options which can only be turned on or off, this
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parameter should be set to <code class="literal">0</code>
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for off and <code class="literal">1</code> for on. Otherwise, set
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this parameter to an integer value that represents the
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number of units for which you are configuring the backup
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APIs.
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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="idp59823888"></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 DB_ENV Handle">DB_ENV</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="idp59844544"></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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<a class="xref" href="envget_backup_config.html" title="DB_ENV->get_backup_config()">DB_ENV->get_backup_config()</a>,
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<a class="xref" href="envbackup.html" title="DB_ENV->backup()">DB_ENV->backup()</a>,
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<a class="xref" href="envdbbackup.html" title="DB_ENV->dbbackup()">DB_ENV->dbbackup()</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_backup_callbacks.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="env.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="envset_data_dir.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">DB_ENV->set_backup_callbacks() </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"> DB_ENV->set_data_dir()</td>
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</tr>
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</table>
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</div>
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</body>
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</html>
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