[ACCEPTED]-What is the difference between a Dead Letter Queue and a back out Queue?-ibm-mq

Accepted answer
Score: 16

The dead letter queue was always used in 16 MQSeries (the last time I used MQ) to store 15 messages that arrived at the queue manager 14 but the queue didn't exist.

For example, if 13 the message was address to queue manager 12 X and queue Y, it would arrive via a channel 11 at manager X.

If the receiver channel discovered 10 there was no queue Y, it would be placed 9 in the dead letter queue.

The backout queue, on 8 the other hand, is more of an application-level 7 thing (at least in terms of MQ). When an 6 MQ client cannot process the message for 5 some reason, it can back it out for later 4 processing (back to it's original queue).

If 3 it's backed out too many times (the threshold 2 can be configured), it gets moved to the 1 backout queue.

Score: 4

Thanks for the answers. I also figured out 9 that if the application is unable to move 8 the message to the Back Out Queue (BOQ) for 7 some reason, then an attempt is made to 6 move the queue to the Dead Letter Queue 5 (DLQ).

In our application it happened. There 4 were some permission issues on the Back 3 Out Queue, so the message could not be written 2 to the BOQ and it ended up in the Dead letter 1 Queue.

Score: 2

The Dead Letter Queue behaves the same as 11 a Backout. I treat the Dead Letter Queue 10 as the Crematorium for messages that cannot 9 be recovered in the Error or Backout queues 8 and have some last, non-business specific 7 data that need be collected. Once the info 6 is captured, the message is put down for 5 good. Backout is good for analyzing messages 4 for data that may need to be recovered to 3 completely reprocess or be sent back to 2 an application area for them to decision 1 on.

Score: 0

A dead letter queue is also a local queue. If 5 we trying to put a message from one queue 4 to another queue and the message was not 3 sent to the correct destination, at this 2 time the meassage will go to a dead letter 1 queue.

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