CODEWITHSUNDEEP
rabbitmqamqp
Richard Tuin
Richard Tuin

Reputation: 4562

Why do I get the same message from RabbitMQ when requeueing?

Background

There are two messages in my queue:

I have one channel, one consumer with Qos active with a prefetch count of 1.

Scenario

A message delivery foo comes in, and I reject the message with requeue=true.

Expected: The next message that is delivered is bar

Actual: The next message that is delivered is foo

Question:

Why does my consumer get the message it just requeued instead of the next one? And how can I get the result described above?

I expected the requeued message to be at the tail of the queue.

I've considered acknowledging and republishing the message, but that opens the risk of losing messages.

Upvotes: 2

Views: 568

Answers (1)

vranac
vranac

Reputation: 94

From the https://www.rabbitmq.com/semantics.html

Messages can be returned to the queue using AMQP methods that feature a requeue parameter (basic.recover, basic.reject and basic.nack), or due to > a channel closing while holding unacknowledged messages. Any of these scenarios caused messages to be requeued at the back of the queue for RabbitMQ releases earlier than 2.7.0. From RabbitMQ release 2.7.0, messages are always held in the queue in publication order, even in the presence of requeueing or channel closure.

Emphasis mine

Because you only have one consumer, this behaviour is expected

You could republish the message to the same queue, that would make sure the problem message ends up on the tail.

Your other option is to create a new queue for failed messages, so you can deal with them separately.

Upvotes: 4

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