Correlation - Start orchestration

Question

I have read on MSDN:
"BizTalk Server 2004 does not support convoy processing when passing in an already initialized correlation set into a new orchestration using the start orchestration. This is because convoy sets handle at the database level, independent of already running
orchestration instances."
Is it true for BizTalk 2010 also?
In this case, if BizTalk doesn't support convoy processing then why would someone want to pass a correlation set? What could be some scenarios in this case?
Thanks.

Answer 1

A Sequential Convoy is typically used to process in-order messages from a queue or debatched source. So it is highly likely that the first and following message will be routed almost immediately.
To accommodate this, the engine has special knowledge of the Sequential Convoy Pattern so it can route/correlate the message as expected.
If they allowed passing of a Correlation Set to a Started Orchestration, the engine would have to somehow know that is going to happen and without scanning the entire Orchestration, wouldn't know that.
In the time it takes to Initialize the first Orchestration, Initialize the Correlation Set, Publish the Start Orchestration Message, Initialize the Start'ed Orchestration, register the Correlation Set, etc. is relatively long compared to routing the second
Convoy message.  Thus, when that second Convoy message is routed, it's highly probable that the Start'ed Orchestration hasn't even been Activated yet and you get the no subscriber error.