Using IBM MQ shared queues for input and output (z/OS)

On z/OS® systems, you can define IBM® MQ shared queues as input and output queues for message flows. You might need to serialize access to those messages.

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Shared queues are available on z/OS only. Use the IBM MQ for z/OS product facilities to define these queues and specify that they are shared.

You cannot use shared queues for integration node component queues such as the SYSTEM.BROKER.CONTROL.QUEUE.

If you use shared queues, you can provide failover support between different images that are running IBM Integration Bus on a sysplex.

Some messaging transactions depend on the exact sequence of messages from a queue, and for that sequence to be maintained in the event of a failure of the queue manager. In these instances, you must serialize the access to those messages.

Serialization of messages is achieved by using specialized connection options and a unique connection token. This connection token is used when the application that empties the messages from a queue issues a connect call to the IBM MQ queue manager that owns that queue.

For example, IBM Integration Bus can use this feature when multiple integration nodes, with multiple integration servers, are each running message flows that empty from a shared input queue. If one broker queue manager fails, the message flow can be started automatically on another integration node. The transactional integrity and original sequencing of the messages on the shared queue are maintained.

To configure shared input queues and define serialization tokens for message flows, follow the instructions in Serialization token - user tasks on z/OS.

For more information, see shared queues in the topic Attributes for shared queues, in the IBM MQ Version 7.5 product documentation online.