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I have a spring message listener configured with 

<bean id="processListenerContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
  <property name="concurrentConsumers" value="1"/>
  <property name="clientId" value="process-execute"/>
  <property name="connectionFactory" ref="topicConnectionFactory"/>
  <property name="destination" ref="processExecuteQueue"/>
  <property name="messageListener" ref="processExecuteListener"/>
</bean>

This is running on a cluster with 2 nodes. I see that it's creating 1 consumer per node rather than 1 per cluster. They're both configured with the above xml so they have the same clientId. Yet, when 2 notifications are posted to the queue, both of the listeners are running, each gets a notification, and both execute in parallel. This is a problem because the notifications need to be handled sequentially.

I can't seem to find out how to make it have only one message listener per cluster rather than per node.

Chip
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  • The spring bean is created on 1 node. It does not have to know anything about the other node. That's why you see consumers on both the nodes. If you need the processing to be done sequentially why do you have 2 nodes in the cluster to start with? Processing only on 1 node and keeping the other ideal is essentially wasting the 2nd node. – TJ- Aug 16 '14 at 12:59
  • Clustering is for automatic fail-over so when node 1 goes down the idle MDP on node 2 will pickup and continue processing without interruption. Also, this is just one small component in the application. I kind of expected the answer to be that MDPs don't have the ability to specify one per cluster :( – Chip Aug 16 '14 at 21:20

1 Answers1

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I solved the problem by having the jms queue block the next consumer until the previous returned. This is a feature in the weblogic server I'm using called Unit of Order. The documentation says you just need to enable it on the queue (I used hash). However, I found that I needed to enable it on the connection factory as well and set a default name. Now I see an MDP per node but 1 waits for 2 to complete before processing and vice versa. Not the solution I intended but it's working nontheless. While oracle specific, it's actually slightly better than a single MDP solution.

Note: I did not set the unit of order name in the spring jmstemplate producer as I do not know if that's possible. I have weblogic setting a default name when none is provided by the producer.

Chip
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