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. Greetings, Andres Freund
