I have a queue that currently has 200 consumers and makes use of message groups. The total number of message groups is unknown but likely to be large (order of 1000s). During periods of particularly heavy load, I see messages destined for this queue arriving on the DLQ with a "TopicSubDiscard" reason. As best I can determine, this suggests that the intended consumers for those messages had a full dispatch queue (still at the default of 1000) so the messages were discarded.
In order to verify this, and to get some indication of whether the group IDs/messages are being evenly distributed across the consumers I try to use the "Active Consumers" screen in the ActiveMQ console, but this shows zero messages enqueues, dequeues, dispatched and dispatch queue for every consumer. I believe that this information is incorrect as the total enqueues/dequeues for the queue in question updates as expected, and some messages are definitely being processed by the consumers. I have not observed any pending messages on this queue even during periods where messages are being discarded.Other queues on the same server do show data on this screen that at least looks realistic. Is there anything that I am likely to have misconfigured that is preventing me from getting at this information, or another way to retrieve it that might be more successful? I'm also open to any suggestions on what might be the root cause of the messages being discarded in the first place. Thanks -- Sent from: http://activemq.2283324.n4.nabble.com/ActiveMQ-User-f2341805.html
