<?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>Replication environment IDs</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="Berkeley DB Programmer's Reference Guide" />
<link rel="up" href="rep.html" title="Chapter 12. Berkeley DB Replication" />
<link rel="prev" href="rep.html" title="Chapter 12. Berkeley DB Replication" />
<link rel="next" href="rep_pri.html" title="Replication environment priorities" />
</head>
<body>
<div class="navheader">
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">Replication environment IDs</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="rep.html">Prev</a> </td>
<th width="60%" align="center">Chapter 12.
Berkeley DB Replication
</th>
<td width="20%" align="right"> <a accesskey="n" href="rep_pri.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="rep_id"></a>Replication environment IDs</h2>
</div>
</div>
</div>
<p>Each database environment included in a replication group must have a
unique identifier for itself and for the other members of the
replication group. The identifiers do not need to be global, that is,
each database environment can assign local identifiers to members of
the replication group as it encounters them. For example, given three
sites: A, B and C, site A might assign the identifiers 1 and 2 to sites
B and C respectively, while site B might assign the identifiers 301 and
302 to sites A and C respectively. Note that it is not wrong to have
global identifiers, it is just not a requirement.</p>
<p>
Replication Manager assigns and manages environment IDs on behalf of
the application.
</p>
<p>It is the responsibility of a Base API application to label each incoming
replication message passed to <a href="../api_reference/C/repmessage.html" class="olink">DB_ENV->rep_process_message()</a> method with the appropriate
identifier. Subsequently, Berkeley DB will label outgoing messages to the
<span class="bold"><strong>send</strong></span> function with those same identifiers.</p>
<p>Negative identifiers are reserved for use by Berkeley DB, and should never be
assigned to environments by the application. Two of these reserved
identifiers are intended for application use, as follows:</p>
<div class="variablelist">
<dl>
<dt>
<span class="term">
<a href="../api_reference/C/reptransport.html#transport_DB_EID_BROADCAST" class="olink">DB_EID_BROADCAST</a>
</span>
</dt>
<dd>
<p>
The <a href="../api_reference/C/reptransport.html#transport_DB_EID_BROADCAST" class="olink">DB_EID_BROADCAST</a> identifier indicates a message should be
broadcast to all members of a replication group.
</p>
</dd>
<dt>
<a id="rep_id.DB_EID_INVALID"></a>
<span class="term">DB_EID_INVALID</span>
</dt>
<dd>
<p>
The DB_EID_INVALID identifier is an invalid environment ID,
and may be used to initialize environment ID variables that
are subsequently checked for validity.
</p>
</dd>
</dl>
</div>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="rep.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="rep.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="rep_pri.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">Chapter 12.
Berkeley DB Replication
</td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> Replication environment priorities</td>
</tr>
</table>
</div>
</body>
</html>
