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<th colspan="3" align="center">Managing Election Times</th>
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<div class="sect1" lang="en" xml:lang="en">
<div class="titlepage">
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<div>
<h2 class="title" style="clear: both"><a id="electiontimes"></a>Managing Election Times</h2>
</div>
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<div class="toc">
<dl>
<dt>
<span class="sect2">
<a href="electiontimes.html#electiontimeout">Managing Election Timeouts</a>
</span>
</dt>
<dt>
<span class="sect2">
<a href="electiontimes.html#electretrytime">Managing Election Retry Times</a>
</span>
</dt>
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<p>
Where it comes to elections, there are two timeout
values with which you should be concerned: election
timeouts and election retries.
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="electiontimeout"></a>Managing Election Timeouts</h3>
</div>
</div>
</div>
<p>
When an environment calls for an election, it will wait
some amount of time for the other replicas in the
replication group to respond. The amount of time
that the environment will wait before declaring the
election completed is the <span class="emphasis"><em>election timeout</em></span>.
</p>
<p>
If the environment hears from all other known replicas before
the election timeout occurs, the election is considered
a success and a master is elected.
</p>
<p>
If only a subset of replicas respond, then the success
or failure of the election is determined by
how many replicas have participated in the
election. It only takes a simple
majority of replicas to elect a master. If
there are enough votes for a given environment to
meet that standard, then the master has been
elected and the election is considered a
success.
</p>
<p>
However, if not enough replicas have participated in
the election when the election timeout value is
reached, the election is considered a failure
and a master is not elected. At this point,
your replication group is operating without a
master, which means that, essentially,
your replicated application has been placed in
read-only mode.
</p>
<p>
Note, however, that the Replication Manager will attempt a
new election after a given amount of time has
passed. See the next section for details.
</p>
<p>
You set the election timeout value using
<code class="methodname">Environment.setReplicationTimeout()</code>.
You pass this method the
<code class="methodname">ReplicationTimeoutType.ELECTION_TIMEOUT</code>
constant and a timeout value in microseconds.
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="electretrytime"></a>Managing Election Retry Times</h3>
</div>
</div>
</div>
<p>
In the event that a election fails (see the
previous section), an election will not be
attempted again until the election retry
timeout value has expired.
</p>
<p>
You set the election timeout value using
<code class="methodname">Environment.setReplicationTimeout()</code>.
You pass this method the
<code class="methodname">ReplicationTimeoutType.ELECTION_RETRY</code>
constant and a retry value in microseconds.
</p>
<p>
Note that this
<span>constant</span> is only
valid when you are using the Replication Manager. If you are
using the Base APIs, then this
<span>constant</span> is
ignored.
</p>
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