Duplicate message handling using Co-relation set

Question

I have orchestion published as service(request-response port).
The service consumer will send duplicate request if no response is received with in time out(configured at application end not biztalk and for example say 2 minutes).
I designed my orchestration to have receive shape first(with corelation initialized) and my some process logic and listen shape(receive with follow co-relation & delay)
All works good when my process logic is successfully executing. But when any failure or delay in processing and duplicate message is received before listen shape, then orchestration supends with error
Request-response operation Operation on port Port is already in progress.
One more contraint is that i need to send response to latest request and there should not be any zombies created.
Plese advice a solution

Answer 1

what you can try is as follows:
Have a receive shape which will initialize a correlation set based on the message properties
then have a parallel shape where in one branch you would do all the processing while in the other you will have another receive shape (following the correlation).
if the request-repeat message is received set an orchestration variable indicating this event (e.g.: duplicate_request = true)
after the parallel shape have a decision based on duplicate request to handle your response. So if you have received the duplicate then respond accordingly otherwise respond to the original request.
What you'd have just done is a set a convoy which will handle duplicate requests without triggering a new orchestration instance.
Regards.