On Wed, Aug 11, 2021 at 11:23 AM Jonathan S. Katz <jk...@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
