On Mon, 2008-07-14 at 21:59 +0200, Kaare Rasmussen wrote: > > I just lost a months worth of stats data myself, so join the club. It > > wasn't critical data, but it would have been nice to have kept > > around... > > I also think there could be a TODO item in it. If vacuum instead of removing > items, somehow stashed them away in a storage limited archive it would be > possible to do a SELECT...AS OF TIMESTAMP. > > The idea is of course to be able to retrieve rows that really are deleted, > but > are still on disk as non-vacuumed or vacuumed and not removed completely. And > it would also take a 2. stage vacuumer to keep the storage within its limits.
I've got the design all worked out for this. The "only" thing we need is a VACUUM that will remove unseen data from within the middle of the sum-of-all-snapshots, if there is a gap. At the moment we never remove rows beyond global xmin, but we could iff the transactions at xmin promise never to update data. That should go on the TODO list as a precursor. Some discussion required :-) -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
