ActiveMQ 消息不断被清除

Question

How to avoid getting purge messages in activemq?

I have front end application (App A) that makes request to back end app (App B) for data via ActiveMQ (version 5.15.8).

When I make a request that retrieves a small amount of data, things work fine as App A gets that data, from App B, and displays it.

However, when App A makes a request to App B (via amq) that retrieves a lot of data, I keep getting this purged message (shown below) in the ActiveMQ active.log and then App A never receives the data.

I should note that App B gets the request from App A, then gets the requested data and forwards it back to ActiveMQ (to then be forwarded to App A). But after sending the data to ActiveMQ this purge message occurs:

2020-03-12 16:29:03,738 | INFO | temp-queue://ID:mcam443-PC-61788-1748020379598-6:1:1 on dispose, purge of 1 pending messages : org.apache.activemq.broker.region.cursors.VMPendingMessageCursor@5d237edf | org.apache.activemq.broker.region.TempQueue | ActiveMQ BrokerService[activemqPrimary] Task-89

Here's my destination policy section of the activemq.xml file

    <destinationPolicy>
        <policyMap>
          <policyEntries>
            <policyEntry queue=">" expireMessagesPeriod="120000" producerFlowControl="true" memoryLimit="5mb">
              <pendingQueuePolicy>
                <vmQueueCursor/>
              </pendingQueuePolicy>
              <pendingMessageLimitStrategy>
                <constantPendingMessageLimitStrategy limit="-1"/>
              </pendingMessageLimitStrategy>

            </policyEntry>
            <policyEntry queue="D.>" expireMessagesPeriod="120000" producerFlowControl="true" memoryLimit="5mb">
              <pendingQueuePolicy>
                <vmQueueCursor/>
              </pendingQueuePolicy>
              <pendingMessageLimitStrategy>
                  <constantPendingMessageLimitStrategy limit="-1"/>
              </pendingMessageLimitStrategy>
            </policyEntry>
          </policyEntries>
        </policyMap>
    </destinationPolicy>

I set the expireMessagesPeriod to be 4 minutes, and I see that App B responds usually within 2 minutes. So that didn't seem to help.

I also set constantPendingMessageLimitStrategy to be -1 which is supposed to disable the discarding of messages ( http://activemq.apache.org/slow-consumer-handling.html )

Again, the purge message doesn't occur when App A makes a request that only returns small amount of data.

How can I avoid getting purge data on large requests? or at all?

Answer 1

Not much information here to go on but from the limited log data it appears the purge message is indicating that you've closed a connection without consuming all messages from a temporary destination and so when the Connection is closed the Temporary Destinations it created are disposed and that one happened to have 1 unconsumed message. The only way to avoid getting that message would be to ensure you've consumed all the messages from the Temp Queue.