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From James Black <be_st...@yahoo.co.uk>
Subject Re: Transaction not started XA problems
Date Thu, 09 Jun 2011 10:06:29 GMT
Hi

ok the problems seems to be that the connection is getting dropped by the
ActiveMQ broker on the server.

I have now verified that the issue occurs when ActiveMQ runs out of heap
available.

I have ran two specific tests.

Note: Although these tests do not allocate that much heap to AMQ we have
seen these issues with much more heap available and believe they would occur
eventually no matter how much heap was allocated.

=== Test 1 ===

Connected our client Tomcat applications to the broker and left them running
overnight.  

I configured the AMQ instance to have only 90MB of heap available to speed
up the process.
With nothing at all occurring on the queues and single topic, the ActiveMQ
installation ran out of heap memory after two hours.

Again there is nothing on the queues or topic during this time.

All that is happening is that the Spring DMLC are polling for new messages.

This then caused the JMS errors related to Atomikos in the application logs.

You can see the GC trying desperately to reclaim memory as the limit is
approached but you can also see a gradual decrease in the amount of memory
that can be GC'ed as time progresses.

=== Test 2 ===

Connected out Tomcat client applications to the broker and ran tests that
pass hundreds of messages per second through the channels.

Again with a setting of 90MB of heap available to ActiveMQ after a period of
30 minutes AMQ ran out of memory and we could see that GC was making no
difference.  I.e. as in test 1 the memory that could be reclaimed with GC
was decreasing as time went on.

We are using persistent storage for our queue and single topic.
Our topic is also durable.

There is very little in the AMQ server logs, occasionally the Out of memory
error will be logged and the disconnection when the heap runs out can be
seen.

Has anyone seen similar behaviour or have any suggestions as to where to go
next?

I have application snapshots (VisualVM) of this issue occurring in test 1.

Thanks to Gary Tully for his help and suggestions previously :>

Thanks,

James

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