On Mon, Nov 29, 2021 at 8:19 PM Justin Pryzby <pry...@telsasoft.com> wrote: > I think the 2nd chunk here could say "if (instrument)" like the first:
I agree that that would be clearer. > Autovacuum's format doesn't show the number of scanned pages ; it shows how > many pages were skipped due to frozen bit, but not how many were skipped due > to > the all visible bit: That's a weird historical accident. I had planned on fixing that as part of ongoing refactoring work [1]. The short explanation for why it works that way goes like this: while it makes zero practical sense (who wants to see how many frozen pages we skipped, without also seeing merely all-visible pages skipped?), it does make some sense when your starting point is the code itself. > If the format of autovacuum output were to change, maybe it's an opportunity > to > show some of the stuff Jeff mentioned: You must be referencing the thread again, from your earlier message -- you must mean Jeff Janes here. Jeff said something about the number of all-visible pages accessed (i.e. not skipped over) being implicit. For what it's worth, that isn't true in the general case -- there simply is no reliable way to see the total number of pages that were skipped using the VM, as of right now. > |Also, I'd appreciate a report on how many hint-bits were set, and how many > |pages were marked all-visible and/or frozen I will probably also add the latter in the Postgres 15 cycle. Hint-bits-set is much harder, and not likely to happen soon. [1] https://postgr.es/m/CAH2-Wznp=c=Opj8Z7RMR3G=ec3_jfgymn_yvmcejopchzwb...@mail.gmail.com -- Peter Geoghegan
