Messages put to a cluster alias queue go to SYSTEM.DEAD.LETTER.QUEUE

A cluster alias queue resolves to a local queue that does not exist.

Symptom

Messages put to an alias queue go to SYSTEM.DEAD.LETTER.QUEUE with reason MQRC_UNKNOWN_ALIAS_BASE_Q.

Cause

A message is routed to a queue manager where a clustered alias queue is defined. A local target queue is not defined on that queue manager. Because the message was put with the MQOO_BIND_ON_OPEN open option, the queue manager cannot requeue the message.

When MQOO_BIND_ON_OPEN is used, the cluster queue alias is firmly bound. The resolved name is the name of the target queue and any queue manager on which the cluster queue alias is defined. The queue manager name is placed in the transmission queue header. If the target queue does not exist on the queue manager to which the message is sent, the message is put on the dead letter queue. The destination is not recomputed, because the transmission header contains the name of the target queue manager resolved by MQOO_BIND_ON_OPEN. If the alias queue had been opened with MQOO_BIND_NOT_FIXED, then the transmission queue header would contain a blank queue manager name, and the destination would be recomputed. In which case, if the local queue is defined elsewhere in the cluster, the message would be sent there.

Solution

1. Change all alias queue definitions to specify DEFBIND ( NOTFIXED).
2. Use MQOO_BIND_NOT_FIXED as an open option when the queue is opened.
3. If you specify MQOO_BIND_ON_OPEN, ensure that a cluster alias that resolves to a local queue defined on the same queue manager as the alias.

Parent topic: Queue manager clusters troubleshooting