"Heikki Linnakangas" <[EMAIL PROTECTED]> writes: > Tom argued that following the tuple chain is cheap enough, and might > even be cheaper than what we have now, that we don't need to prune just > for the purpose of keeping the chains short. To which I pointed out that > currently, without HOT, we mark index tuples pointing to dead tuples as > killed to avoid following them in the future, so HOT without pruning is > not cheaper than what we have now.
That hack only works in plain indexscans, though, not bitmapped scans. Anyway, I remain unconvinced that the chains would normally get very long in the first place, if we could prune when updating. The we-already-pinned-the-page problem is a bit nasty but may not be insurmountable. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org