Message flow in a shared-queues environment

In a shared-queues environment, when an IMS retrieves a message from a shared queue, the message is locked on that shared queue until the IMS unlocks or deletes the message. If IMS does not unlock or delete a message from the shared queue (for example, because of an IMS abend), the message remains locked.

Locked messages are not available to other IMS systems for processing. If you cold start the IMS after it locks messages on a shared queue, those messages remain locked, and they are moved to the cold queue.

If RM is defined with a resource structure, IMS releases any locked messages destined for an LTERM on the failing IMS. Messages become available to a user signing on to another IMS in the IMSplex.