On Wed, 2008-05-28 at 16:55 -0400, Gregory Stark wrote: > "Simon Riggs" <[EMAIL PROTECTED]> writes: > > > So the idea is to have one pass per VACUUM, but make that one pass do > > the first pass of *this* VACUUM and the second pass of the *last* > > VACUUM. > > I think that's exactly the same as the original suggestion of having HOT > pruning do the second pass of the last vacuum. The trick is to know whether > the last vacuum committed or not. If it didn't commit then it's not safe to > remove those line pointers yet.
Perhaps, though I'm not suggesting storing extra xids on-block. I think if we have to wait for a VACUUM to run before marking the line pointers then we may as well wait for two. Having something wait for a VACUUM and then removed it by HOT afterwards gives you the worst of both worlds: long wait for a VACUUM then more overhead and extra code during HOT pruning. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
