On Tue, 2010-03-16 at 15:29 +0000, Greg Stark wrote: > I'm picturing storing a bit in the visibility map indicating that *no* > records are visible in a given page.
I've been thinking for a while that we could store the visibility information in a structure separate from the heap -- sort of like the visibility map, but per-tuple and authoritative rather than a per-page hint. There are all kinds of challenges there, but it might be worth thinking about. Visibility information is highly compressible, and requires constant maintenance (updates, deletes, freezing, etc.). It also might make it possible to move to 64-bit xids, if we wanted to. Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers