An user reported to me about a problem that happened to him once during merge:
PagingChannelSupport couldn't load the the exact number of messages:
java.lang.IllegalStateException: Did not load correct number of messages, wanted:3331 but got:3330 at org.jboss.messaging.core.impl.PagingChannelSupport.processReferences(PagingChannelSupport.java:579) at org.jboss.messaging.core.impl.PagingChannelSupport.doLoad(PagingChannelSupport.java:497) at org.jboss.messaging.core.impl.MessagingQueue.mergeIn(MessagingQueue.java:223) at org.jboss.messaging.core.impl.postoffice.MessagingPostOffice.performFailover(MessagingPostOffice.java:2918) at org.jboss.messaging.core.impl.postoffice.MessagingPostOffice.nodesLeft(MessagingPostOffice.java:917) at org.jboss.messaging.core.impl.postoffice.GroupMember$ControlMembershipListener$1ViewChangeRunnable.run(GroupMember.java:489) at java.lang.Thread.run(Thread.java:595)
This is an old one
http://jira.jboss.com/jira/browse/JBMESSAGING-908