On 05/31/2013 12:22 PM, Stephen Frost wrote:
> Where I'm going with this whole thing is simply that I do worry a bit
> about using a bitmap for freeze, or similar, information and not being
> able to reconstruct that bitmap from the heap. Perhaps that's overly
> paranoid, but, well, we also write the same data out to disk in multiple
> places multiple times- some might call that paranoid too. ;)
On the other hand, we could combine Heikki's proposal (epoch numbers in
the page header) together with using the visibility map for pages we
don't need to vacuum freeze, and get vastly better behavior without
increasing corruption risk that I can see.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com