e!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 4//EN"> Queue Manager Clusters: Using your own cluster workload exits

Using your own cluster workload exits

You may write your own cluster workload exit and override the WebSphere MQ default behaviour. On non-z/OS platforms, using CLWLMode=FAST each operating system process loads its own copy of the exit, and different connections to the queue manager can cause different copies of the exit to be invoked. When the exit is run in the default safe mode, CLWLMode=SAFE, a single copy of the exit runs in its own separate process. For more information on how to set CLWLMode see theWebSphere MQ System Administration Guide. Below is the round robin algorithm which WebSphere MQ uses by default.

Algorithm: The steps in choosing a destination for a message:

  1. If a queue name is specified, eliminate queues that are not PUT enabled.

    Eliminate remote instances of queues that do not share a cluster with the local queue manager.

    Eliminate remote CLUSRCVR channels that are not in the same cluster as the queue.

  2. If a queue manager name is specified, eliminate queue manager alias' that are not PUT enabled.

    Eliminate remote CLUSRCVR channels that are not in the same cluster as the local queue manager.

  3. If the result above contains the local instance of the queue, choose it.

  4. If the message is a cluster PCF message, eliminate any queue manager you have already sent a publication or subscription to.

  5. If only remote instances of a queue remains, choose Resumed queue managers over Suspended ones.

  6. If more than one remote instance of a queue remains, include all MQCHS_INACTIVE and MQCHS_RUNNING channels.

  7. If less than one remote instance of a queue remains, include all MQCHS_BINDING, MQCHS_INITIALIZING, MQCHS_STARTING, and MQCHS_STOPPING channels.

  8. If less than one remote instance of a queue remains, include all MQCHS_RETRYING channels.

  9. If less than one remote instance of a queue remains, include all MQCHS_REQUESTING, MQCHS_PAUSED and MQCHS_STOPPED channels.

  10. If more than one remote instance of a queue remains and the message is a cluster PCF message, choose locally defined CLUSSDR channels.

  11. If more than one remote instance of a queue remains to any queue manager, choose channels with the highest NETPRTY to each queue manager.

  12. If more than one remote instance of a queue remains, choose the least recently used channel.

 

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IBM is a trademark of the IBM Corporation in the United States, other countries, or both.