On Thu, Feb 10, 2022 at 11:16 AM Robert Haas <robertmh...@gmail.com> wrote: > On Thu, Feb 10, 2022 at 3:10 AM Dilip Kumar <dilipbal...@gmail.com> wrote: > > Actually I was not worried about the scan getting slow. What I was > > worried about is if we keep ignoring the dead tuples for long time > > then in the worst case if we have huge number of dead tuples in the > > index maybe 80% to 90% and then suddenly if we get a lot of insertion > > for the keys which can not use bottom up deletion (due to the key > > range). So now we have a lot of pages which have only dead tuples but > > we will still allocate new pages because we ignored the dead tuple % > > and did not vacuum for a long time. > > It seems like a reasonable concern to me ... and I think it's somewhat > related to my comments about trying to distinguish which dead tuples > matter vs. which don't.
It's definitely a reasonable concern. But once you find yourself in this situation, *every* index will need to be vacuumed anyway, pretty much as soon as possible. There will be many LP_DEAD items in the heap, which will be enough to force index vacuuming of all indexes. -- Peter Geoghegan
