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Programming considerations

 

Applications can open a queue using the MQOPEN call. Applications use the MQPUT call to put messages onto an open queue. Applications can put a single message onto a queue that is not already open, using the MQPUT1 call.

If you set up clusters that do not have multiple instances of the same queue, there are no specific application programming considerations. However, to benefit from the workload management aspects of clustering, you might need to modify your applications. If you set up a network in which there are multiple definitions of the same queue, review your applications for message affinities as described in Reviewing applications for message affinities.

Also, be aware of the following:

1. If an application opens a target queue so that it can read messages from it or set its attributes, the MQOPEN call operates only on the local version of the queue.

2. If an application opens a target queue so that it can write messages to it, the MQOPEN call chooses between all available instances of the queue when at least one of the following is true:

   • A local version of the target queue does not exist.

   • The queue manager specifies CLWLUSEQ(ANY) on ALTER QMGR.

   • The queue on the queue manager specifies CLWLUSEQ(ANY).

• Reviewing applications for message affinities
  

 

Parent topic:

Using clusters for workload management

qc11000_

 

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