RabbitMQ - purge a queue from all of its unacked messages

Question

I have thousands of unacked messages in my dev environment which I can\'t restart.
Is there a way to remove (purge) all messages even if they are unacknowledged?

Answer 1

You have to make consumer ack them (or nack) and only after that they will be removed. Alternatively you can shutdown consumers and purge the queue completely.

If you are looking for some way to purge all unacked messages - there are no such feature nor in AMQP protocol neither in RabbitMQ.

It looks like your consumer is the cause of the problem, so you have to adjust it (rewrite) to release message immediately after it processed or failed.

Answer 2

Once there are no "ready" messages in the queue, delete it and recreate.

Answer 3

You need to call basic.recover to force all unacked messages to be re-enqueued to a channel that failed. Be aware of the errata concerning this function specifying that only the requeue mode is supported by RabbitMQ.

Answer 4

For software developer use below code.

channel.purgeQueue(queue-name);

if we use this code the Queue will be clear and same queue will exist.

Answer 5

One way this can happen is if the consumer is stuck recycling the same messages due to a processing error. In this case, the RabbitMQ queue management interface may show the messages as Unacked, but really they are being read from the queue and processed (to the point of the failure) then requeued (to enable a retry) at a rapid pace -- maybe thousands of times per second.

During this loop, the messages exist briefly in the Ready state, but are immediately removed again by you application -- and the cycle begins again. As an example, this auto-requeue behavior is the default for Spring AMQP.

Since the messages are never left in the Ready state, the Management Interface's Get Message(s) button is unlikely work. What can work, if you have queue access, is to run a separate custom consumer instance, perhaps locally, but with the specific intent of removing and not requeuing the messages in question.

By RabbitMQ's Fair Dispatch mechanism, your additional consumer will likely receive the messages in question and have the opportunity to perform your custom handling.

You might even write a custom utility to do this, with logic to filter, analyze, or deadletter the messages of interest.

Answer 6

Close the channel that the unacked messages reside on, which will nack them back into the queue, then call purge.