Dead-letter queues

 

---

Overview

The dead-letter queue (or undelivered-message queue) is the queue to which messages are sent if they cannot be routed to their correct destination. Messages are put on this queue when they cannot be put on the destination queue for some reason (for example, because the queue does not exist, or because it is full). Dead-letter queues are also used at the sending end of a channel, for data-conversion errors.

We recommend that you define a dead-letter queue for each queue manager. If you do not, and the MCA is unable to put a message, it is left on the transmission queue and the channel is stopped.

Also, if fast, non-persistent messages cannot be delivered and no DLQ exists on the target system, these messages are discarded.

However, using dead-letter queues can affect the sequence in which messages are delivered, and so you may choose not to use them.