Any update on this ? Also, is there a way that I can check the queue size/length through some command for a threshold.
The client should be decoupled from the message consumer.
When do you see the behaviour and how do you measure it.
i.e. if you undeploy the MDB you are still able to send messages into the queue, but there is no consumer.
Yes, I agree that the client should be decoupled. To give you the complete scenario, the MDB code which I have was slow (nothing wrong on JBoss at this point), the code was having some exceptions causing each message to be consumed probably a second or two later than expected. This was filling up the queue pretty fast because as I told, the client sends hundreds of messages/minute. I noticed the Messages in queue and In Delivery on the console, both were around 1,000 [This was the same on 3 JBoss instances on different servers which I have]. At this point, the client would slow down, since JBoss server was not accepting messages as normally it would. Once I killed the JBoss instances, the client would not connect to JBoss and it was functioning normally.