HornetQ: Remove all messages from queue not working with consumer on queue

Question

I have a simple test case where I start a HornetQ server (V2.4.7.Final) as part of a Spring context. This works quite well and I have access to a queue via JMS, the HornetQ API and/or JMX.

Testcase

The test case is supposed to empty the queue at start, check that it is empty and then add 10 messages to the queue. As long as there are no consumers on this queue, this works using either the management queue or JMSQueueControl. Even doing some operation on the queue via JMX is working well.

Problem description

As soon as I add a message listener to this queue using Spring configuration - and the listener consumes the messages as expected - I cannot remove all messages from the queue. Neither method invocation via JMX, nor the management queue, nor JMSQueueControl is working, i.e. the methods are called without exception but they show no effect.

I thought that maybe I have to pause the queue before doing some modifications to its content but pausing does not work either. I can see that the queue is paused via JMX and the same is reported when using the API but the consumer still consumes messages from the very queue. Thus I think it has not been paused at all.

I know that it is difficult without the source code but from my point of view this is all pretty basic setup as you find it in many, many tutorials. Could anyone give advice what I am doing wrong. In case any source code is needed, please leave a comment and I will add the revelant parts.

Answer 1

HornetQ supports removal of messages which are in the queue on the broker side. Once the messages are dispatched to the consumer and buffered on the consumer, it is not possible to remove the messages from the consumer buffer using any management API.

One way to solve this (if you must) is to disable consumer buffering by setting the consumer-window-size to 0, but be aware of the potential performance degradation.

Otherwise, you need to handle it programmatically; by adding some validity checks before processing the message.

You can read more about HornetQ Flow control here https://docs.jboss.org/hornetq/2.2.5.Final/user-manual/en/html/flow-control.html