On Tue, Dec 21, 2021 at 12:46 PM Andres Freund <and...@anarazel.de> wrote: > > Hi, > > On 2021-12-20 17:17:26 -0800, Peter Geoghegan wrote: > > On Thu, Dec 9, 2021 at 8:41 PM Bossart, Nathan <bossa...@amazon.com> wrote: > > > I like the idea of having a built-in function that does the bare > > > minimum to resolve wraparound emergencies, and I think providing some > > > sort of simple progress indicator (even if rudimentary) would be very > > > useful. > > > > If John doesn't have time to work on this during the Postgres 15 > > cycle, and if nobody else picks it up, then we should at least do the > > bare minimum here: force the use of the failsafe in single user mode > > (regardless of the age of relfrozenxid/relminmxid, which in general > > might not be that old in tables where VACUUM might need to do a lot of > > work). Attached quick and dirty patch shows what this would take. If > > nothing else, it seems natural to define running any VACUUM in single > > user mode as an emergency. > > As I said before I think this is a bad idea. I'm fine with adding a vacuum > parameter forcing failsafe mode. And perhaps a hint to suggest it in single > user mode. But forcing it is a bad idea - single user isn't just used for > emergencies (c.f. initdb, which this patch would regress) and not every > emergency making single user mode useful is related to wraparound.
+1 BTW a vacuum automatically enters failsafe mode under the situation where the user has to run a vacuum in the single-user mode, right? Regards, -- Masahiko Sawada EDB: https://www.enterprisedb.com/
