2 Replies Latest reply on Jan 7, 2010 9:25 AM by scott selikoff

    AMQ-1112:  Removing expired messages

    scott selikoff Newbie

      Has the Fuse team considering incorporating AMQ-1112 into future releases of the Fuse message broker?  As this Blog Article points out, if you are using message selectors, such a fix is vital to prevent hung queues.


      The root of the issue is that the message broker does not remove messages as soon as they expire, but rather the next time a message is popped off the queue.  The AMQ-1112 fix inserts a worker thread that checks X number of messages of a queue every Y milliseconds (with X and Y being configurable parameters) and expires messages found to be out of date.


      I've reproduced the 'hung queue' issue as mentioned in the blog.  Simply stated, create a queue with size = 10, then create 10 messages for a specific message selector, say myWidget=6, and send them to the queue.  Now create 10 more messages for a different message selector, say myWidget=7.  At this point, if a listener with (myWidget=6) does not connect to the queue or is otherwise unavailable, no widget (myWidget=7 or otherwise) will be able to obtain any messages even though some were sent and the queue is otherwise hung.  Only two listeners will be able to clear the queue, those with no message selector set (in this case they get all the messages) and those set to myWidget=6, which may be offline.


      I reproduced the issue with both small and large queue sizes and it does lock up the queue.  Any idea if and when AMQ-1112 or a similar solution may be incorporated into Fuse?