On Wed, Aug 11, 2021 at 11:23 AM Jonathan S. Katz <jkatz@postgresql.org> wrote:
> How about:
>
> * `pg_upgrade` now carries forward the old installation's `oldestXID`
> value, which can improve things from a performance standpoint by no
> longer forcing an anti-wraparound `VACUUM`.
I don't think that framing this as a performance thing really makes
sense. It certainly helps performance to not do something that's
totally unnecessary, and only ever happened because of a bug in the
implementation. But to me the point is that we're not doing these
weird wholly unnecessary antiwraparound VACUUMs on upgrade now.
Running pg_upgrade no longer affects when or how we VACUUM, which is
exactly what you'd expect all along.
--
Peter Geoghegan
