Hi,
> I'm surprised that these patches extend the page numbering to 64 bits,
> but never actually uses the high bits. The XID "epoch" is not used, and
> pg_xact still wraps around and the segment names are still reused. I
> thought we could stop doing that.
To clarify, the idea is to let CLOG grow indefinitely and simply store
FullTransactionId -> TransactionStatus (two bits). Correct?
I didn't investigate this in much detail but it may affect quite some
amount of code since TransactionIdDidCommit() and
TransactionIdDidCommit() currently both deal with TransactionId, not
FullTransactionId. IMO, this would be a nice change however, assuming
we are ready for it.
In the previous version of the patch there was an attempt to derive
FullTransactionId from TransactionId but it was wrong for the reasons
named above in the thread. Thus is was removed and the patch
simplified.
--
Best regards,
Aleksander Alekseev