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From Wayne1285 <WayneSIr...@hotmail.com>
Subject Race Condition?
Date Fri, 28 Apr 2006 05:55:31 GMT

I am using ActiveMq-4.0-RC3.  I have been having intermittent problems
getting sessions created and closed.  I have downloaded the code and traced
through it and I think I have found the problem.  

There is a race conditon in the TcpTransport class, in the doStart() method. 
As near as I can tell, as soon as the socket is created, the Broker responds
with its WireFormatInfo.  This information is usually stored as the
remoteWireFormatInfo in the InactivityMonitor.  The race condition occurs in
the doStart() method as it appears the broker can sometimes send the
wireFormatInfo before the initializeStreams() method can be called.  This
results in the information not being capture in the dataIn input buffer.  

Once this occurs, this sets up the session hangs that I have been
experiencing.  Since the remoteWireFormatInfo was never captured from the
broker, requests to InactivityMonitor.startMonitorThreads() does not start
as the condition of having a remoteWireFormatInfo is not met and the method
just returns.  That causes not socket activities at all. The original thread
eventually proceeds to the WireFormatNegotiator.oneway(command) method that
issues a readyCountDownLatch.await(); which is never met and never times
out.

I have written a thread to call the create session function and give it a
maximum of 15 seconds to complete.  If the thread exceeds that time, it is
sent an interrupt, but that does not seem to interrupt the
readyCountDownLatch.await(). Eventually I get all these hung threads that I
cannot clean up.

I would liike to see if the race conditon can be fixed, but in addition why
I cannot issue an interrupt against this thread when it gets into this
state.
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