[jboss-dev-forums] [Design of Messaging on JBoss (Messaging/JBoss)] - Re: JBM 2.0 Strict ordering via ordering groups

[timfox]

"gaohoward" wrote : 
  | 1. consumers of strict ordered messages cannot receive second message without first being acknowledged. 
  | 

I don't agree. For ordering there is no requirement that previous message is acked first - that's an implementation detail. The only requirement is that messages are delivered in order.


anonymous wrote : 
  | 2. If we can guarantee strict ordering, there is no need to nail the ordered messages to one consumer. Consider if there are two consumers on one queue that deliver ordered messages. If one consumer gets a failure situation and is not able to consume anymore, the current message will not be acked (or will be rolled back), the other consumer may take over the job (as backup) and continue working (it may call session.recover() first). Will message group allow that happen?
  | 

Yes, with message grouping, if a consumer closes, another consumer will get pinned to that group.

anonymous wrote : 
  | 3. If user only wants message group, he shouldn't pay the performance cost brought by strict ordering.
  | 

What performance penalty is that?

anonymous wrote : 
  | 4. In failover and cluster cases, message group and strict ordering are handled differently. Consumer identity is critical for a message group to survive a failure, but sequence is vital to ordering.
  | 

I didn't understand this last point. Can you elaborate?

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