Re: do only critical work during single-user vacuum?

On Tue, Feb 15, 2022 at 1:04 AM John Naylor
<john(dot)naylor(at)enterprisedb(dot)com> wrote:
> Well, the point of inventing this new vacuum mode was because I
> thought that upon reaching xidStopLimit, we couldn't issue commands,
> period, under the postmaster. If it was easier to get a test instance
> to xidStopLimit, I certainly would have discovered this sooner. When
> Andres wondered about getting away from single user mode, I assumed
> that would involve getting into areas too deep to tackle for v15. As
> Robert pointed out, lazy_truncate_heap is the only thing that can't
> happen for vacuum at this point, and fully explains why in versions <
> 14 our client's attempts to vacuum resulted in error. Since the
> failsafe mode turns off truncation, vacuum should now *just work* near
> wraparound. If there is any doubt, we can tighten the check for
> entering failsafe.

+1 to all of that.

--
Robert Haas
EDB: http://www.enterprisedb.com