Can't change ActiveMQ redeliveryPolicy

Question

We're using ActiveMQ 5.14.2.1 triggered by the Java Windows service wrapper, accessing from a Tomcat webapp using JMS and the Spring framework JMS (v4.3.28).

I'm trying to configure a redelivery policy so that when we return the message to the queue using session.rollback() it follows the policy. To do this, I set up the redeliveryPlugin in the activemq.xml file as follows:

<amq:redeliveryPlugin fallbackToDeadLetter="true" sendToDlqIfMaxRetriesExceeded="true">
    <amq:redeliveryPolicyMap>
        <amq:redeliveryPolicyMap>
            <amq:defaultEntry>
                <amq:redeliveryPolicy maximumRedeliveries="20" useExponentialBackOff="true" 
initialRedeliveryDelay="1000" redeliveryDelay="2000" maximumRedeliveryDelay="600000"/>
            </amq:defaultEntry>
        </amq:redeliveryPolicyMap>
    </amq:redeliveryPolicyMap>
</amq:redeliveryPlugin>

I also updated the broker element to turn on schedulerSupport:

<amq:broker brokerName="MyBroker" dataDirectory="${activemq.data}" 
            useJmx="false" schedulerSupport="true">

I've tried a few permutations of this based on various documentation pages and several SO results, without success. Whatever I try it's using the default redelivery behavior (1 second between, no exponential backoff, max of 6 retries). I know it's reading this activemq.xml file, because when I put content that doesn't match the XSD it errors out.

What do I have to do to alter ActiveMQ's redelivery policy?

@JustinBertram Yup. Will update. – fool4jesus May 19 '21 at 22:05 — fool4jesus, May 19 '21 at 22:05

fool4jesus · Accepted Answer · 2021-05-21T18:21:09.877

After lots of investigation and poking around in ActiveMQ with the debugger, I figured out what's going on. It turns out the configuration above is basically correct. I modified it slightly to:

<amq:redeliveryPolicy maximumRedeliveries="20" useExponentialBackOff="true" 
     initialRedeliveryDelay="5000" backOffMultiplier="2" maximumRedeliveryDelay="600000"/>

What is confusing though is the client side AND the server are both trying to do retries, but it appears they use different algorithms:

The client side initially makes 6 re-attempts, 1 second apart.
If those all fail, it sends the message back to ActiveMQ
ActiveMQ performs the redelivery behavior, which means to use the initial redelivery delay (5 sec)
If the messages still fail, the client again does re-tries at 1 second intervals, but this time it only makes 5 attempts.
ActiveMQ again does redelivery behavior, doubling the delay to 10s.
Upon re-delivery, the client again retries, but this time only 4 times before sending the message back to ActiveMQ.

This cycle keeps going, with the client reducing the number of local retries by 1 each time, and ActiveMQ increasing the retry time using exponential backoff. Finally, ActiveMQ sends the message at 10 minute intervals (the maximum delay), with the client doing 0 local retries on failures. I guess the idea in the client is to try to let the code solve the problem locally a few times, but it figures over time this becomes decreasingly likely.

Can't change ActiveMQ redeliveryPolicy

1 Answers1