This section describes the limitations of intra-group queuing.
Because intra-group queuing makes use of a shared transmission queue that is defined in the Coupling Facility (CF), intra-group queuing is limited to delivering messages of the maximum supported message length for shared queues minus the length of a transmission queue header (MQXQH).
Only one IGQ agent is started per queue manager in a queue-sharing group.
The IGQ agent is started during queue manager initialization and terminated during queue manager shut-down. It is designed to be a long running, self recovering (in the event of abnormal termination), task. If there is an error with the definition of the SYSTEM.QSG.TRANSMIT.QUEUE (for example, if this queue is Get inhibited) the IGQ agent keeps retrying. If the IGQ agent should encounter an error that results in normal termination of the agent while the queue manager is still active, it can be restarted by issuing an ALTER QMGR IGQ(ENABLED) command. This avoids the need to recycle the queue manager.