CODEWITHSUNDEEP
rabbitmqspring-amqpreliabilitydead-letter
John Donn
John Donn

Reputation: 1858

RabbitMQ dead letter handling guarantees

If I use publisher confirms, I can be (reasonably) sure that a message sent to an exchange on the RabbitMQ server, and which received ACK from the RabbitMQ server is not lost even if the RabbitMQ server crashes (power outage for example).

However what happens when a message arrives at a dead letter exchange after a manual rejection in the consumer? (channel.basicReject, I use Spring AMQP.)

Can I still be sure that in the case in which the original message is dequeued from the queue to which the consumer is listening, and the RabbitMQ server subsequently crashes, I will eventually find the message, after the RabbitMQ server is restarted, in the queues which are bound to the dead letter exchange (if normally the message would have arrived there)?

If the answer is negative, is there a way to ensure that this is the case?

Upvotes: 2

Views: 597

Answers (1)

John Donn
John Donn

Reputation: 1858

As @GaryRussell suggested, I posted a similar question on rabbitmq-users Google group.

Here is the answer I got from Daniil Fedotov

"Hi,

There is no delivery guarantees in place. Dead lettering does not check if the message was enqueued or saved to disk.
Dead-lettering does not use publisher confirms or any other confirm mechanisms.

It's not that easy to implement reliable dead-lettering from one queue to another and there are plans to address this issue eventually, but it may take a while.

If you want to safely reject messages from the consumer without a risk of losing them - you can publish them from the consumer application manually to the dead-letter queue, wait for the confirmation and then reject."

Upvotes: 2

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