[xmlblaster] Callback message queue fills up

[David R Robison <drrobison at openroadsconsulting.com>]

We are experiencing something strange in xmlBlaster 1.6.1. We have two 
nodes, node A subscribes to messages from node B. These are heartbeat 
messages and are generated every 15 seconds with a lifetime of 30 
seconds. A client connects to node A and subscribes to the messages, 
node A then passes the subscription onto node B. Watching the callback 
message queue, everything seems to run well, at most 1 message in the 
queue waiting to be sent. It can run like this for days. Then, 
unexpectedly, the callback queue will show as being full (in this case 
1001 messages). The queue contains many duplicated messages with 
different timestamps. From there, the server struggles to deliver the 
messages and keep the queue empty. The reader never seems to read enough 
messages to get the queue back down to zero. If I stop the client and 
reconnect, it will recreate its queue and be back to normal. I know this 
is a bit sketchy, but it is becoming a real problem for us.

Any thoughts on what might be the problem? Any idea of where to start 
looking?

One more note, when the client is subscribing to heartbeats that are 
generated on Node A, the client never fails in this manor, only when it 
is subscribing to node A for a message generated on node B.

Thanks, in advance,
David Robison

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David R Robison
Open Roads Consulting, Inc.
708 S. Battlefield Blvd., Chesapeake, VA 23322
phone: (757) 546-3401
e-mail: drrobison at openroadsconsulting.com
web: http://openroadsconsulting.com
blog: http://therobe.blogspot.com
book: http://www.xulonpress.com/book_detail.php?id=2579