2011-09-13 17:44:24 +00:00
|
|
|
|
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
|
|
|
|
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
|
|
|
|
<html xmlns="http://www.w3.org/1999/xhtml">
|
|
|
|
|
|
<head>
|
|
|
|
|
|
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
|
|
|
|
|
|
<title>Managing Heartbeats</title>
|
|
|
|
|
|
<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
|
|
|
|
|
|
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
|
|
|
|
|
|
<link rel="start" href="index.html" title="Getting Started with Replicated Berkeley DB Applications" />
|
|
|
|
|
|
<link rel="up" href="repapp.html" title="Chapter 3. The DB Replication Manager" />
|
|
|
|
|
|
<link rel="prev" href="fmwrkconnectretry.html" title="Managing Connection Retries" />
|
|
|
|
|
|
<link rel="next" href="fwrkmasterreplica.html" title="Chapter 4. Replica versus Master Processes" />
|
|
|
|
|
|
</head>
|
|
|
|
|
|
<body>
|
|
|
|
|
|
<div xmlns="" class="navheader">
|
|
|
|
|
|
<div class="libver">
|
2012-11-14 21:35:20 +00:00
|
|
|
|
<p>Library Version 11.2.5.3</p>
|
2011-09-13 17:44:24 +00:00
|
|
|
|
</div>
|
|
|
|
|
|
<table width="100%" summary="Navigation header">
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<th colspan="3" align="center">Managing Heartbeats</th>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td width="20%" align="left"><a accesskey="p" href="fmwrkconnectretry.html">Prev</a> </td>
|
|
|
|
|
|
<th width="60%" align="center">Chapter 3. The DB Replication Manager</th>
|
|
|
|
|
|
<td width="20%" align="right"> <a accesskey="n" href="fwrkmasterreplica.html">Next</a></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
</table>
|
|
|
|
|
|
<hr />
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="sect1" lang="en" xml:lang="en">
|
|
|
|
|
|
<div class="titlepage">
|
|
|
|
|
|
<div>
|
|
|
|
|
|
<div>
|
|
|
|
|
|
<h2 class="title" style="clear: both"><a id="heartbeats"></a>Managing Heartbeats</h2>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<p>
|
|
|
|
|
|
If your replicated application experiences few updates,
|
|
|
|
|
|
it is possible for the replication group to lose a
|
|
|
|
|
|
master without noticing it. This is because normally a
|
|
|
|
|
|
replicated application only knows that a master has
|
|
|
|
|
|
gone missing when update activity causes messages to be
|
|
|
|
|
|
passed between the master and replicas.
|
|
|
|
|
|
</p>
|
|
|
|
|
|
<p>
|
|
|
|
|
|
To guard against this, you can configure a heartbeat.
|
|
|
|
|
|
The heartbeat must be configured for both the master
|
|
|
|
|
|
and each of the replicas.
|
|
|
|
|
|
</p>
|
|
|
|
|
|
<p>
|
|
|
|
|
|
On the master, you configure the application to send a
|
|
|
|
|
|
heartbeat on a defined interval when it is otherwise
|
|
|
|
|
|
idle. Do this by using the
|
|
|
|
|
|
<span>
|
|
|
|
|
|
<code class="literal">DB_REP_HEARTBEAT_SEND</code> value
|
|
|
|
|
|
to the <code class="literal">which</code> parameter of the
|
|
|
|
|
|
|
|
|
|
|
|
<code class="methodname">DbEnv::rep_set_timeout()</code>
|
|
|
|
|
|
method.
|
|
|
|
|
|
</span>
|
|
|
|
|
|
|
|
|
|
|
|
You must also provide the method a value representing the period between heartbeats in microseconds. Note that the heartbeat is sent only if the
|
|
|
|
|
|
system is idle.
|
|
|
|
|
|
</p>
|
|
|
|
|
|
<p>
|
|
|
|
|
|
On the replica, you configure the application to listen
|
|
|
|
|
|
for a heartbeat. The time that you configure here is
|
|
|
|
|
|
the amount of time the replica will wait for some
|
|
|
|
|
|
message from the master (either the heartbeat or some
|
|
|
|
|
|
other message) before concluding that the connection is
|
|
|
|
|
|
lost. You do this using the
|
|
|
|
|
|
<span>
|
|
|
|
|
|
<code class="literal">DB_REP_HEARTBEAT_MONITOR</code> value
|
|
|
|
|
|
to the <code class="literal">which</code> parameter of the
|
|
|
|
|
|
|
|
|
|
|
|
<code class="methodname">DbEnv::rep_set_timeout()</code>
|
|
|
|
|
|
method and a timeout value in microseconds.
|
|
|
|
|
|
</span>
|
|
|
|
|
|
|
|
|
|
|
|
</p>
|
|
|
|
|
|
<p>
|
|
|
|
|
|
For best results, configure the heartbeat monitor for a
|
|
|
|
|
|
longer time interval than the heartbeat send interval.
|
|
|
|
|
|
</p>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="navfooter">
|
|
|
|
|
|
<hr />
|
|
|
|
|
|
<table width="100%" summary="Navigation footer">
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td width="40%" align="left"><a accesskey="p" href="fmwrkconnectretry.html">Prev</a> </td>
|
|
|
|
|
|
<td width="20%" align="center">
|
|
|
|
|
|
<a accesskey="u" href="repapp.html">Up</a>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td width="40%" align="right"> <a accesskey="n" href="fwrkmasterreplica.html">Next</a></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr>
|
|
|
|
|
|
<td width="40%" align="left" valign="top">Managing Connection Retries </td>
|
|
|
|
|
|
<td width="20%" align="center">
|
|
|
|
|
|
<a accesskey="h" href="index.html">Home</a>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td width="40%" align="right" valign="top"> Chapter 4. Replica versus Master Processes</td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
</table>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</body>
|
|
|
|
|
|
</html>
|
