What to do if messages are building up on the SYSTEM.FTE queue on the coordination queue manager

The coordination queue manager for an IBM® MQ Managed File Transfer (MFT) topology uses queued publish/subscribe to process status publications and distribute them to subscribers.

The publish/subscribe engine of the queue manager use a publication stream to monitor the SYSTEM.FTE queue for incoming publications. When it receives one, it makes copies of it to distribute to subscribers.

Under normal operation, the SYSTEM.FTE queue should be empty or contain only a handful of messages. If the queue depth continues to grow, then it usually means that the publish/subscribe engine is no longer using the publication stream. This typically happens if the coordination queue manager has recently been recreated.

To resolve this issue, you should check that the SYSTEM.QPUBSUB.QUEUE.NAMELIST namelist has been set up correctly and contains an entry for the SYSTEM.FTE queue. To do this, run the following MQSC command:

DISPLAY NAMELIST(SYSTEM.QPUBSUB.QUEUE.NAMELIST)

This should generate output similar to the following example:

NAMELIST(SYSTEM.QPUBSUB.QUEUE.NAMELIST)
NAMCOUNT(3)
NAMES(SYSTEM.BROKER.DEFAULT.STREAM
        ,SYSTEM.BROKER.ADMIN.STREAM
        ,SYSTEM.FTE)
DESCR(A list of queues for the queued Pub/Sub interface to monitor)
ALTDATE(2022-03-04)                     ALTTIME(14.34.37)

If the NAMES attribute does not include SYSTEM.FTE, you can add it using the following MQSC command:

ALTER NAMELIST(SYSTEM.QPUBSUB.QUEUE.NAMELIST) NAMES(SYSTEM.BROKER.DEFAULT.STREAM,SYSTEM.BROKER.ADMIN.STREAM,SYSTEM.FTE)