nms/activemq-consumer-priority.xml

<div class="wiki-content maincontent"><h3 id="ActiveMQConsumerPriority-Background">Background</h3>

<p>As well as having a pluggable dispatch policy (e.g. round robin etc), we now support consumer priorities.</p>

<p>This allows us to weight consumers to optimise network hops. For example, you typically want a broker to send messages to regular NMS consumers rather than to other brokers; there's no need to make unnecessary broker-to-broker hops if there are available consumers.</p>

<h3 id="ActiveMQConsumerPriority-Example">Example</h3>

<p>The priority for a consumer is set using <a shape="rect" href="activemq-uri-configuration.xml">Destination Options</a> as follows:</p>

<div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
<script class="brush: java; gutter: false; theme: Default" type="syntaxhighlighter"><![CDATA[
var queue = session.GetQueue(&quot;TEST.QUEUE?consumer.priority=10&quot;);
var consumer = session.CreateConsumer(queue);
]]></script>
</div></div>

<p>The range for assigning priority numbers is from 0 to 127, with 127 being the highest priority and 0 being the default priority.<br clear="none">
The way it works is that the broker will simply order any queue consumers according to their priorities and send messages to the highest priority consumers first. <br clear="none">
Once a particular consumer has its prefetch buffer filled up, the broker will begin to dispatch messages to consumers of lower priorities. </p></div>