On Mon, 2007-09-10 at 18:23 +0100, Heikki Linnakangas wrote: > > If we check a tuple in a chain and the tuple is dead is it possible the > > pruning operation is cheaper than having to check the tuple again for > > visibility the next time we see it? If so, we can just always prune > > when we see a dead tuple in the chain, which I believe was the original > > design. Pruning becomes an operation similar to marking an index entry > > as dead. (I assuming pruing does not generate WAL traffic.) > > Pruning does generate a WAL record at the moment. Maybe you could do > some kind of a quick pruning without a WAL record. Like just modify the > ctid of the oldest dead tuple in the chain, or the redirecting line > pointer if there is one, to point to the latest live tuple, without > removing the dead tuples or the line pointers.
Sounds like a great idea. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org