RE: [Quickfix-users] Session resync problem

[Ajay K. <Aja...@tr...>]

You might want to consider using the
ThreadedSocketAcceptor/ThreadedSocketInitiator classes that will place
each Session on its own thread, which I expect should prevent the other
sessions getting starved while the engine is busy servicing the resend
requests in a tight loop. Obviously your application would need to be
thread safe to go this route. Caveat emptor: Not having actually used
these classes myself yet, this suggestion is based upon theoritical
analysis. YMMV.
=20
- Ajay

	-----Original Message-----
	From: Sean Kirkpatrick
[mailto:sea...@pi...]=20
	Sent: Tuesday, March 07, 2006 9:05 AM
	To: qui...@li...
	Subject: [Quickfix-users] Session resync problem
=09
=09

	Hello All,=20

	We had an issue in our production environment that boiled down
to the following:=20

	1. Client has hard disconnect=20
	2. We send some messages prior to detecting the session is down=20
	3. Client logs back in with higher than expected seq num and
immediately starts sending some messages=20
	4. We send resend reqs for each message we receive until they
are handled, which the client does by=20
	    sending us seq reset messages.=20
	5. The client heartbeats.=20
	6. At this point, we do some message resending.=20
	-- this is where the trouble began --=20
	7. Since the client did not sync its seq nums after the logon,
when we start sending these messages they=20
	    have higher than expected seq nums.=20
	8. Client sends a resend request for each of the messages we
sent (125).=20

	When processing the resend requests, the engine sits in a tight
loop processing its queue.  The trouble=20
	here is that the resend requests took approx. 5 minutes to get
through and all other connections were=20
	starved.=20

	Has anyone come across this problem, or have a suggestion for
dealing with it gracefully?=20

	Regards,=20

	Sean Kirkpatrick=20