Synchronization queue for queue sharing groups

Shared channels have their own shared synchronization queue called SYSTEM.QSG.CHANNEL.SYNCQ.

This synchronization queue is accessible to any member of the queue sharing group. (Private channels continue to use the private synchronization queue. See Defining IBM MQ objects ). This means that the channel can be restarted on a different queue manager and channel initiator instance within the queue sharing group in the event of failure of the communications subsystem, channel initiator, or queue manager. For further information, see Preparing IBM MQ for z/OS for DQM with queue sharing groups.

DQM with queue sharing groups requires that a shared queue is available with the name SYSTEM.QSG.CHANNEL.SYNCQ. This queue must be available so that a group listener can successfully start.

If a group listener fails because the queue was not available, the queue can be defined and the listener can be restarted without recycling the channel initiator. The non-shared channels are not affected.

Make sure that you define this queue using INDXTYPE(MSGID). This definition improves the speed at which messages on the queue can be accessed.