On Wed, Aug 9, 2023 at 6:18 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Perhaps, though, there's a case for forcing all pages to be visited
> if we start with reltuples == -1? I'm not sure it matters much
> though given that you also need an ANALYZE run to be really in a
> good place after pg_upgrade. The ANALYZE should update this.
Right. VACUUM is sometimes much less efficient than just using ANALYZE
to establish an initial reltuples. Other times it is much less
accurate. I can't see any argument for opting to use VACUUM instead of
ANALYZE after an upgrade.
--
Peter Geoghegan