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HTML
202 lines
11 KiB
HTML
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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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<html xmlns="http://www.w3.org/1999/xhtml">
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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>Replication Manager methods</title>
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<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
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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 Programmer's Reference Guide" />
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<link rel="up" href="rep.html" title="Chapter 12. Berkeley DB Replication" />
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<link rel="prev" href="rep_app.html" title="Building replicated applications" />
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<link rel="next" href="rep_base_meth.html" title="Base API Methods" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 11.2.5.2</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">Replication Manager methods</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="rep_app.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 12.
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Berkeley DB Replication
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="rep_base_meth.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="rep_mgr_meth"></a>Replication Manager methods</h2>
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</div>
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</div>
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</div>
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<p>
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Applications which use the Replication Manager support generally
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call the following Berkeley DB methods. The general pattern is to
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call various methods to configure Replication Manager, and then
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start it by calling <a href="../api_reference/C/repmgrstart.html" class="olink">DB_ENV->repmgr_start()</a>. Once this initialization is
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complete, the application rarely needs to call any of these
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methods. (A prime example of an exception to this rule would be
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the <a href="../api_reference/C/repsync.html" class="olink">DB_ENV->rep_sync()</a> method, if the application is
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<a class="xref" href="rep_mastersync.html#rep_delay_sync" title="Delaying client synchronization">Delaying client synchronization</a>.)
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</p>
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<div class="variablelist">
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<dl>
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<dt>
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<span class="term">
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<a href="../api_reference/C/db_site.html" class="olink">DB_SITE</a>
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</span>
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</dt>
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<dd>
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<p>
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The <a href="../api_reference/C/db_site.html" class="olink">DB_SITE</a> handle is used to configure a site that
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belongs to the replication group. You can obtain a <a href="../api_reference/C/db_site.html" class="olink">DB_SITE</a>
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handle by calling the <a href="../api_reference/C/repmgr_site.html" class="olink">DB_ENV->repmgr_site()</a> method. When you do this, you
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provide the TCP/IP host name and port that the replication
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site uses for incoming connections.
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</p>
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<p>
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Once you have the <a href="../api_reference/C/db_site.html" class="olink">DB_SITE</a> handle, you use the
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<a href="../api_reference/C/dbsite_set_config.html" class="olink">DB_SITE->set_config()</a> method to configure the handle. One of
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the things you can configure about the handle is whether it
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is the local site (using the <code class="literal">DB_LOCAL_SITE</code>
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parameter). You must configure one and only one <a href="../api_reference/C/db_site.html" class="olink">DB_SITE</a> handle
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to be a local site before you start replication.
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</p>
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<p>
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You can also optionally configure <a href="../api_reference/C/db_site.html" class="olink">DB_SITE</a> handles for
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remote sites to help Replication Manager startup more
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efficiently. Note that it is usually not necessary for
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each site in the replication group initially to know about
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all other sites in the group. Sites can discover each
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other dynamically, as described in
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<a class="xref" href="rep_newsite.html" title="Connecting to a new site">Connecting to a new site</a>.
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</p>
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<p>
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Once you have configured your <a href="../api_reference/C/db_site.html" class="olink">DB_SITE</a> handles, you start
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replication using <a href="../api_reference/C/repmgrstart.html" class="olink">DB_ENV->repmgr_start()</a>.
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</p>
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<p>
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When you are shutting down your application, you must
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use the <a href="../api_reference/C/dbsite_close.html" class="olink">DB_SITE->close()</a> method to close
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all your open <a href="../api_reference/C/db_site.html" class="olink">DB_SITE</a> handles before you close your
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environment handles.
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</p>
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</dd>
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<dt>
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<span class="term">
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<a href="../api_reference/C/repmgrset_ack_policy.html" class="olink">DB_ENV->repmgr_set_ack_policy()</a>
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</span>
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</dt>
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<dd>
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<p>
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The <a href="../api_reference/C/repmgrset_ack_policy.html" class="olink">DB_ENV->repmgr_set_ack_policy()</a> method configures the acknowledgement
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policy to be used in the replication group, in other words, the
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behavior of the master with respect to acknowledgements for
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"permanent" messages, which implements the application's
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requirements for <a class="xref" href="rep_trans.html" title="Transactional guarantees">Transactional guarantees</a>. The current implementation
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requires all sites in the replication group to configure the same
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acknowledgement policy.
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</p>
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</dd>
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<dt>
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<span class="term">
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<a href="../api_reference/C/reppriority.html" class="olink">DB_ENV->rep_set_priority()</a>
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</span>
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</dt>
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<dd>
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<p>
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The <a href="../api_reference/C/reppriority.html" class="olink">DB_ENV->rep_set_priority()</a> method configures the local site's priority
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for the purpose of elections.
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</p>
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</dd>
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<dt>
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<span class="term">
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<a href="../api_reference/C/repset_timeout.html" class="olink">DB_ENV->rep_set_timeout()</a>
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</span>
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</dt>
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<dd>
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<p>
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This method optionally configures various timeout values.
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Otherwise default timeout values as specified in <a href="../api_reference/C/repset_timeout.html" class="olink">DB_ENV->rep_set_timeout()</a>
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are used. In particular, Replication Manager client sites can
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be configured to monitor the health of the TCP/IP connection to
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the master site using heartbeat messages. If the client
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receives no messages from the master for a certain amount of
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time, it considers the connection to be broken, and calls for
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an election to choose a new master.
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</p>
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</dd>
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<dt>
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<span class="term">
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<a href="../api_reference/C/envevent_notify.html" class="olink">DB_ENV->set_event_notify()</a>
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</span>
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</dt>
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<dd>
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<p>
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Once configured and started, Replication Manager does virtually
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all of its work in the background, usually without the need for
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any direct communication with the application. However,
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occasionally events occur which the application may be
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interested in knowing about. The application can request
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notification of these events by calling the <a href="../api_reference/C/envevent_notify.html" class="olink">DB_ENV->set_event_notify()</a>
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method.
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</p>
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</dd>
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<dt>
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<span class="term">
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<a href="../api_reference/C/repmgrstart.html" class="olink">DB_ENV->repmgr_start()</a>
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</span>
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</dt>
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<dd>
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<p>
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The <a href="../api_reference/C/repmgrstart.html" class="olink">DB_ENV->repmgr_start()</a> method starts the replication system. It
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opens the listening TCP/IP socket and creates all the
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background processing threads that will be needed.
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</p>
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</dd>
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</dl>
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</div>
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<p>
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In addition to the methods previously described, Replication Manager
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applications may also call the following methods, as needed:
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<a href="../api_reference/C/repconfig.html" class="olink">DB_ENV->rep_set_config()</a>, <a href="../api_reference/C/repset_limit.html" class="olink">DB_ENV->rep_set_limit()</a>, <a href="../api_reference/C/repset_request.html" class="olink">DB_ENV->rep_set_request()</a>, <a href="../api_reference/C/repsync.html" class="olink">DB_ENV->rep_sync()</a> and <a href="../api_reference/C/repstat.html" class="olink">DB_ENV->rep_stat()</a>.
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</p>
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<p>
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Finally, Replication Manager applications can also make use of the
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Replication Manager's message channels. This allows the various
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sites in the replication group to pass messages that are tailored
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to the application's requirements. For more information, see
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<a class="xref" href="repmgr_channels.html" title="Using Replication Manager message channels">Using Replication Manager message channels</a>.
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</p>
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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="rep_app.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="rep.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="rep_base_meth.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">Building replicated applications </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"> Base API Methods</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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