Hi Alastair,
I read Choreology's initial submission and have a couple remarks/comments.
1. Requirement #1: Operation groups with reverse operations.
For some operations (e.g booking an airline ticket, deposit, withdrawal),
defining compensation (reverse operations) is pretty straightforward.
However, how difficult will it be to define compensations for more
complex
operations especially when they use differing isolation/durability
levels (e.g. the operation may have done some dirty reads).
2. Requirements #8 and #9. Is relaxing isolation and durability sufficient
to capture the consistency requirements for business transactions?
Are there other parameters?
The example that is in my head is a simple procurement example.
A purchaser initiates an order, due to a time out the
order is cancelled. However it suddenly arrives or the the supplier
tells the purchaser that the goods were delayed for some reason
and are now on their way by express delivery, the purchaser then
decides to proceed with the order - that is, re-instate the
initial order (compensate for the compensation). By the time the
purchaser wants to re-instate the order, payment may to the supplier
may have been cancelled and so payment need to be re-instated.
Since isolation is relaxed, the payment may have been canceled by the
time the order is re-instated.
Is the scenario a scenario that should be supported by a business
transaction protocol? Is so, how and how does the requirements
capture this scenario?
3. I like the approach of identifying the requirements before defining a
protocol. We are doing this down here (where the beef is safe
to eat :-) Sorry) as well.
Dean
==================================================================
Dean Kuo
Senior Research Scientist
Software Architecture and Component Technologies Group
CSIRO Mathematical and Information Sciences Tel: +61 2 6216 7066
GPO Box 664 ACTON ACT 2601 Australia Fax: +61 2 6216 7111
==================================================================
> -----Original Message-----
> From: Alastair Green [mailto:]
> Sent: Tuesday, 13 March 2001 9:14 AM
> To:
> Subject: Choreology initial submission to OASIS BT TC
>
>
> Our apologies for the last-minute delivery of this initial
> submission on
> scope and requirements for the proposed BT protocol.
>
> Alastair Green, Peter Furniss
> Choreology Ltd
>
>
