Why is not message in a queue redistributed to another node in cluster?

[jan.novak]

I have two nodes in a cluster running JBoss 5.1 AS and providing a clustered JMS queue. There is a consumer running on another machine connecting to the clustered queue and processing messages from it. The message producers are running on the JBoss cluster and produce messages to queue on both nodes.

In this case, I run into a situation when there is a message on one node, consumer on the other node and the message is not being consumed. I would expected that the node with the consumer would pull the message from the second node, but this does not happen. Is my expectation not correct or is there a configuration error / issue in JBoss Messaging?

Using:

JBoss AS 5.1

JBoss Messaging 1.4.6

JBoss Remoting 2.5.4.SP4

The queue has attribute clustered set to true. In messaging-service.xml, there is <attribute name="ClusterPullConnectionFactoryName">jboss.messaging.connectionfactory:service=ClusterPullConnectionFactory</attribute>.

[dgrove_redhat.com]

Messages can, don't don't always, move between nodes.  For example, there is a configuration parameter "PrefetchSize" on the connection factory that tells the factory how many messages to cache in memory.  A message that has been prefetched will not move between nodes.

[jan.novak]

Thanks a lot for the suggestion, Doug!

I have checked and indeed the prefetch size is set. I will try to repeat the scenario with having this in mind and verify with more messages than the prefetch size.