On Thu, Dec 9, 2021 at 1:04 PM Peter Geoghegan <p...@bowt.ie> wrote: > On Thu, Dec 9, 2021 at 11:28 AM John Naylor > <john.nay...@enterprisedb.com> wrote: > > Now that we have a concept of a fail-safe vacuum, maybe it would be > > beneficial to skip a vacuum in single-user mode if the fail-safe > > criteria were not met at the beginning of vacuuming a relation. > > Obviously the main goal of the failsafe is to not get into this > situation in the first place. But it's still very reasonable to ask > "what happens when the failsafe even fails at that?". This was > something that we considered directly when working on the feature.
Oh, I think I misunderstood. Your concern is for the case where the DBA runs a simple "VACUUM" in single-user mode; you want to skip over tables that don't really need to advance relfrozenxid, automatically. I can see an argument for something like that, but I think that it should be a variant of VACUUM. Or maybe it could be addressed with a better user interface; single-user mode should prompt the user about what exact VACUUM command they ought to run to get things going. -- Peter Geoghegan