Heikki,
This sounds a lot like my idea for 9.3, which didn't go anywhere.
You've worked out the issues I couldn't, I think.
> Another method is
> to store the 32-bit xid values in tuple headers as offsets from the
> per-page 64-bit value, but then you'd always need to have the 64-bit
> value at hand when interpreting the XIDs, even if they're all recent.
Yeah, -1 on the latter, not least because it would require a 100%
rewrite of the tables in order to upgrade.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com
