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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->repmgr_set_ack_policy()</title>
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<link rel="stylesheet" href="apiReference.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 C API Reference" />
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<link rel="up" href="rep.html" title="Chapter 10. Replication Methods" />
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<link rel="prev" href="repmgr_msg_dispatch.html" title="DB_ENV->repmgr_msg_dispatch()" />
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<link rel="next" href="repmgr_site.html" title="DB_ENV->repmgr_site()" />
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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">DB_ENV->repmgr_set_ack_policy()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="repmgr_msg_dispatch.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 10.
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Replication Methods
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="repmgr_site.html">Next</a></td>
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</tr>
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</table>
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<hr />
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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="repmgrset_ack_policy"></a>DB_ENV->repmgr_set_ack_policy()</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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int
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DB_ENV->repmgr_set_ack_policy(DB_ENV *env, int ack_policy); </pre>
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<p>
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The <code class="methodname">DB_ENV->repmgr_set_ack_policy()</code> method specifies how master and
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client sites will handle acknowledgment of replication messages which are necessary for
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"permanent" records. The current implementation requires all sites in a replication group
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configure the same acknowledgement policy.
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</p>
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<p>
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The database environment's replication subsystem may also be configured using the
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environment's <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file. The
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syntax of the entry in that file is a single line with the string "repmgr_set_ack_policy",
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one or more whitespace characters, and the <span class="bold"><strong>ack_policy</strong></span>
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parameter specified as a string. For example, "repmgr_set_ack_policy DB_REPMGR_ACKS_ALL".
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Because the <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is read
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when the database environment is opened, it will silently overrule configuration done
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before that time.
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</p>
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<p>
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Waiting for client acknowledgements is always limited by the
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<a class="link" href="repset_timeout.html#set_timeout_DB_REP_ACK_TIMEOUT">DB_REP_ACK_TIMEOUT</a>
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specified by the <a class="xref" href="repset_timeout.html" title="DB_ENV->rep_set_timeout()">DB_ENV->rep_set_timeout()</a> method.
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If an insufficient number of client acknowledgements have been
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received, then the master will invoke the event callback function,
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if set, with the
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<a class="link" href="envevent_notify.html#event_notify_DB_EVENT_REP_PERM_FAILED">DB_EVENT_REP_PERM_FAILED</a>
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value.
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(See the
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<a href="../../programmer_reference/rep_mgr_ack.html" class="olink">
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Choosing a Replication Manager Ack Policy
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</a>section in the
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<em class="citetitle">Berkeley DB Programmer's Reference Guide</em> for more information.)
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</p>
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<p>
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The <code class="methodname">DB_ENV->repmgr_set_ack_policy()</code> method configures a database
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environment, not only 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.
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</p>
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<p>
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The <code class="methodname">DB_ENV->repmgr_set_ack_policy()</code> method may be called at any time
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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->repmgr_set_ack_policy()</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="id3933076"></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="id3933197"></a>ack_policy</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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Some acknowledgement policies use the concept of an
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electable peer, which is a client capable of being
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subsequently elected master of the replication
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group. The <span class="bold"><strong>ack_policy</strong></span> parameter
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must be set to one of the following values:
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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><a id="ackspolicy_DB_REPMGR_ACKS_ALL"></a>
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<span class="bold"><strong>DB_REPMGR_ACKS_ALL</strong></span>
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</p>
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<p>
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The master should wait until all replication clients have acknowledged
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each permanent replication message.
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</p>
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</li>
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<li>
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<p><a id="ackspolicy_DB_REPMGR_ACKS_ALL_AVAILABLE"></a>
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<span class="bold"><strong>DB_REPMGR_ACKS_ALL_AVAILABLE</strong></span>
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</p>
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<p>
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The master should wait until all currently connected replication clients have acknowledged
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each permanent replication message.
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This policy will then invoke the
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<a class="link" href="envevent_notify.html#event_notify_DB_EVENT_REP_PERM_FAILED">DB_EVENT_REP_PERM_FAILED</a> event if fewer than
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a quorum of clients acknowledged
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during that time.
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</p>
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</li>
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<li>
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<p><a id="ackspolicy_DB_REPMGR_ACKS_ALL_PEERS"></a>
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<span class="bold"><strong>DB_REPMGR_ACKS_ALL_PEERS</strong></span>
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</p>
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<p>
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The master should wait until all electable peers have acknowledged
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each permanent replication message.
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</p>
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</li>
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<li>
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<p><a id="ackspolicy_DB_REPMGR_ACKS_NONE"></a>
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<span class="bold"><strong>DB_REPMGR_ACKS_NONE</strong></span>
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</p>
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<p>
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The master should not wait for any client replication message
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acknowledgments.
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</p>
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</li>
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<li>
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<p><a id="ackspolicy_DB_REPMGR_ACKS_ONE"></a>
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<span class="bold"><strong>DB_REPMGR_ACKS_ONE</strong></span>
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</p>
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<p>
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The master should wait until at least one client site has acknowledged
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each permanent replication message.
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</p>
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</li>
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<li>
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<p><a id="ackspolicy_DB_REPMGR_ACKS_ONE_PEER"></a>
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<span class="bold"><strong>DB_REPMGR_ACKS_ONE_PEER</strong></span>
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</p>
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<p>
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The master should wait until at least one electable peer has
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acknowledged each permanent replication message.
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</p>
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</li>
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<li>
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<p><a id="ackspolicy_DB_REPMGR_ACKS_QUORUM"></a>
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<span class="bold"><strong>DB_REPMGR_ACKS_QUORUM</strong></span>
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</p>
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<p>
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The master should wait until it has received acknowledgements from the
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minimum number of electable peers sufficient to ensure that the effect
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of the permanent record remains durable if an election is held. This is the default acknowledgement
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policy.
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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>
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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="id3933843"></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">DB_ENV->repmgr_set_ack_policy()</code>
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<span>
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<span>
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method may fail and return one 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="id3933708"></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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If this method is called from a base replication API
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application; or if an invalid flag value or parameter was
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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="id3933899"></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="id3933947"></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="rep.html#replist" title="Replication and Related Methods">Replication 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="repmgr_msg_dispatch.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="repmgr_site.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->repmgr_msg_dispatch() </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->repmgr_site()</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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