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ydsk · Posted: Mon Dec 04, 2006 3:03 am Post subject:

Not sure if I need to post this in MQ specific forums but this is related to both broker and MQ.

I have a question related to setting MQ priority in a clustered broker ( WBIMB ) environment.

We have 2 msg brokers clustered with a bunch of application qmgrs, all in one big v 5.3 MQ cluster, each qmgr on a different box.

An application wants to send messages thru its qmgr - all with default priority onto 2 clustered message brokers and we were asked to set the priority on each msg within the broker ( in a msgflow by scanning a part of the msg ) before delivering the msg on a target application qmgr's queue. Basically, they want 2 priorities - High and Normal. The High priority msgs are very very low volume but they need to be processed by the target application within a specified time.

This is our first application asking for priority to be set by broker. So far, all the applications have been using default priority.

I am thinking that setting priority on the brokers might pose problems going forward ( though we are ok for now as the volume is very less) when more applications ask for it because all the msgs go thru the CLUSTER TRANSMIT queue on either broker and we might start seeing long delays when msgs go from the cluster transmit queue to the target application's qmgr ( due to higher priority msgs being constantly delivered/available on the target application's queues, which are processed before the other msgs ). We might see more delays when applications start asking for more than 2 priorities in future.

An alternative approach I thought of is to have 2 separate target queues on the application qmgr for messages of different priorities so that the brokers deliver msgs to the right priority queue without actually setting/changing the priority on any message. This would keep the broker environment clean and would avoid applications causing "side-effects" on one another.

Of course, this approach would work only if the applications agree to using multiple queues on their target qmgrs. Otherwise, I think setting priority is the only way for us.

---- Also pls tell me, which of the following 2 statements is correct --------

1) Setting the priority of a msg within the msgflow and then sending it to the target application qmgr's clustered queue would raise the priority on only the channel connecting to the target qmgr. It doesn't affect other lower/normal priority msgs sitting on the cluster transmit queue.

2) Or do all the msgs on the broker going thru the cluster xmit queue wait for the hight priority message to process first.

If the second statement above is correct, we don't want to set priority of a msg within the broker. If the first statement is correct, we probably will.

Appreciate a clear response/advice.

Thanks very much.
ydsk.