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<title>Berkeley DB Reference Guide: Replication environment IDs</title>
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<td><h3><dl><dt>Berkeley DB Reference Guide:<dd>Berkeley DB Replication</dl></h3></td>
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<h1 align=center>Replication environment IDs</h1>
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<p>Each database environment included in a replication group must have a
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unique identifier for itself and for the other members of the
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replication group. The identifiers do not need to be global, that is,
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each database environment can assign local identifiers to members of
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the replication group as it encounters them. For example, given three
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sites: A, B and C, site A might assign the identifiers 1 and 2 to sites
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B and C respectively, while site B might assign the identifiers 301 and
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302 to sites A and C respectively. Note that it is not wrong to have
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global identifiers, it is just not a requirement.
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<p>It is the responsibility of the application to label each incoming
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replication message passed to <a href="../../api_c/rep_message.html">DB_ENV->rep_process_message</a> method with the appropriate
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identifier. Subsequently, Berkeley DB will label outgoing messages to the
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<b>send</b> interface with those same identifiers.
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<p>Negative identifiers are reserved for use by Berkeley DB, and should never be
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assigned to environments by the application. Two of these reserved
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identifiers are intended for application use, as follows:
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<p><dt><a href="../../api_c/rep_transport.html#DB_EID_BROADCAST">DB_EID_BROADCAST</a><dd>The <a href="../../api_c/rep_transport.html#DB_EID_BROADCAST">DB_EID_BROADCAST</a> identifier indicates a message should be
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broadcast to all members of a replication group.
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<p><dt><a href="../../api_c/rep_transport.html#DB_EID_INVALID">DB_EID_INVALID</a><dd>The <a href="../../api_c/rep_transport.html#DB_EID_INVALID">DB_EID_INVALID</a> identifier is an invalid environment ID, and
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may be used to initialize environment ID variables that are subsequently
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