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<title>ActiveMQ Artemis Delayed Redelivery Example</title>
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<h1>Delayed Redelivery Example</h1>
<pre>To run the example, simply type <b>mvn verify</b> from this directory, <br>or <b>mvn -PnoServer verify</b> if you want to start and create the server manually.</pre>
<p>This example demonstrates how ActiveMQ Artemis can be configured to provide a delayed redelivery in the case
where a message needs to be redelivered.</p>
<p>Delaying redelivery can often be useful in the case that clients regularly fail or roll-back. Without a delayed
redelivery, the system can get into a "thrashing" state, with delivery being attempted, the client rolling back, and
delivery being re-attempted ad infinitum in quick succession, using up valuable CPU and network resources.</p>
<p>Re-delivery occurs when the session is closed with unacknowledged messages. The unacknowledged messages will
be redelivered.</p>
<p>By providing a redelivery delay, it can be specified that a delay of, say, 10 seconds is implemented between rollback
and redelivery. The specific delay is configurable on both a global and per destination level, by using wild-card
matching on the address settings.</p>
<h2>Example setup</h2>
<p>Redelivery delay is specified in the configuration file <a href="src/main/resources/activemq/server0/broker.xml">broker.xml</a>:</p>
<p>In this example we set the redelivery delay to 5 seconds for the specific example queue. We could set redelivery delay on
on multiple queues by specifying a wild-card in the match, e.g. <code>match="jms.#"</code> would apply the settings
to all JMS queues and topics.</p>
<p>We then consume a message in a transacted session, and rollback, and note that the message is not redelivered until
after 5 seconds.</p>
<pre class="prettyprint">
<code><address-setting match="jms.queue.exampleQueue">
<redelivery-delay>5000</redelivery-delay>
</address-setting>
</code>
</pre>
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