Re: Open-top coordinators and protocol

[Mark Little <mcl@arjuna.com>]

Just in case this has been missed in what we have been saying: I am in
favour of piggybacking messages where possible. However, I do not believe
that we should come up with a protocol that mandates it or requires it
because such optimisations may not be possible, or may get in the way of,
for example, debugging (one of your examples requiring the disabling of
interposition). I would have thought that we could come up with a protocol
specification that could address this.

For example, in the OTS when using interposition it is entirely legal to
delay registration of the subordinate coordinator until the response of the
actual application message flows back, simply because the context flows back
on the response as well. If we do not preclude reverse context propagation,
then such optimisations may actually be more natural.

Mark.

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SENDER : Dr. Mark Little, Architect (Transactions), HP Arjuna Labs
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