Tech and Tips

With JMS persistent messages, all the message are persisted to the storage device by default, but also kept in memory. When a queue can potentially contain many messages, it is then necessary to set a max memory allowed, like this:

<broker xmlns="http://activemq.apache.org/schema/core" brokerName="localhost" dataDirectory="/var/activemq/data">
    <destinationPolicy>
        <policyMap>
            <policyEntries>
                <policyEntry queue=">" producerFlowControl="false" memoryLimit="100mb" queuePrefetch=”1” maxPageSize=”10” lazyDispatch=”true” />
            </policyEntries>
        </policyMap>
    </destinationPolicy>
</broker>