Hi,
>> I think we even can just do something like a global
>> TransactionId check_if_transaction_is_alive = InvalidTransactionId;
>> and just set it up during decoding. And then just check it whenever it's
>> not set tot InvalidTransactionId.
>>
>>
>
> Ok. I will work on something along these lines and re-submit the set of patches.
>
PFA, latest patchset, which completely removes the earlier
LogicalLock/LogicalUnLock implementation using groupDecode stuff and
uses the newly suggested approach of checking the currently decoded
XID for abort in systable_* API functions. Much simpler to code and
easier to test as well.
Out of the patchset, the specific patch which focuses on the above
systable_* API based XID checking implementation is part of
0003-Gracefully-handle-concurrent-aborts-of-uncommitted-t.patch. So,
it might help to take a look at this patch first for any additional
feedback on this approach.
There's an additional test case in
0005-Additional-test-case-to-demonstrate-decoding-rollbac.patch which
uses a sleep in the "change" plugin API to allow a concurrent rollback
on the 2PC being currently decoded. Andres generally doesn't like this
approach :-), but there are no timing/interlocking issues now, and the
sleep just helps us do a concurrent rollback, so it might be ok now,
all things considered. Anyways, it's an additional patch for now.
Comments, feedback appreciated.
Regards,
Nikhils
--
Nikhil Sontakke http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services