>I suppose one could use a qualifier on FAULT to
point to the message / parameter that caused the problem.
>>Since we can
potentially compound many different messages and not just BEGIN/CONTEXT, I
would suggest that we need some general mechanism that allows users to
determine exactly where the error occurred.
I
agree on having a general mechanism to determine where and what exactly
happened in case of faults with compound messages. Reference mechanism will be
needed especially for FAULTs in compound messages.
Also, do we describe what should happen if fault
occurs for 2nd out of 3-related-message group compound message? Should actions
of the whole group be reversed or only of the failed
message? Compound messages are processed in order. That means, if 2nd
message fails, 3rd message is never processed. However, what about the
effects of the 1st message? Should it be reversed? This is even
difficult if an application message is present in that group. Is the effect of
compound message group atomic? I think not. So, it seems failures in Compound
Messages deserve a paragraph or two in "Failure Recovery" section to
address all such questions.
sanjay
I guess that the spec is not very heavy at
present on error reporting - it takes a relatively light, but probably
adequate, touch.
I think as far as error reporting is concerned
"adequate" is not good enough in a distributed system. It's hard enough to
track down problems locally without having to factor in
remoteness.
I think that what you are highlighting is
actually a problem when you have more than one BTP message travelling
together - which one does a FAULT message in reply refer to? I
suppose one could use a qualifier on FAULT to point to the message /
parameter that caused the problem.
With regards to BEGIN, would you like to propose
some text for us to consider?
Since we can potentially compound many different
messages and not just BEGIN/CONTEXT, I would suggest that we need some
general mechanism that allows users to determine exactly where the error
occurred. However, specifically for BEGIN I'd suggest adding text along the
lines of "If BEGIN is accompanied by a CONTEXT then the additional FAULT of
WrongState may be returned."
Mark.
----------------------------------------------
Dr.
Mark Little, Distinguished Engineer,
Transactions Architect, HP Arjuna
Labs
Email: mark_little@hp.com
Phone: +44 191
2606216
Fax : +44 191 2606250