Batch Processing of Messages creating problems

Hi All,

I've a web service, that puts messages on MSMQ, Biztalk picks them up from MSMQ, calls the subscribed orchestration, in that orchestration we call a .net component, which uses oracle to run a SP, and then gives back the result to Orchestration, It makes a new message according to that result, puts it back to MSMQ and Web Service, which is polling for that message using a correlation ID, picks it up. That completes the cycle.

By default on Recieve port, Ordered Processing is set to false, with batch size = 20. The probelm we were facing with this setting was, when we opened the web-service in the browser, and repeatidly invoked it with the same message, it returned with different results, not each time, but like 3 results were same, 4 were other etc. It was random and some of those were correct replies for that request message.

When we changed the Ordered Processing to true, and batch size =1,  and repeated the same procedure, all the replies were same and correct. I am very surprised at this behaviour of Biztalk, because if we are submitting messages in a batch, why is it returning multiple replies for same message?, Please shed some light on this, and what is the difference b/w Ordered and Not Ordered Messaging?

Regards,

Sajid.