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

[ataylor]

anonymous wrote : What's the advantage in allowing multiple consumers? If you're ordering, then by definition, you will need to serialise consumption 

I was just taking this from the comments on the Jira, 'In order to guarantee strict ordering, even on rollback or in the presence of multiple consumers or with xa transactions, the queue needs to ensure that no more than one message with the value of ordering group is being delivered at any one time.'

anonymous wrote : I'm not sure I understand that, can you elaborate? 

So you send 10 messages, 5 for group A, with seq 1 to 5, and 5 for group B again with seq 1 to 5. A consumer consumes message group A seq 1 but does not acknowledge, the next message in group A with seq 2 can't be delivered but message group B seq 1 can, This gives you strict ordering within the defined group.

 anonymous wrote : Why would message groups deliver messages out of order? I don't follow that either.

The producer can specify on send the sequence number of a message to specify its delivery order.

View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4193863#4193863

Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4193863