| From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Justin Pryzby <pryzby(at)telsasoft(dot)com>, pgsql-hackers(at)lists(dot)postgresql(dot)org, Matthias van de Meent <boekewurm+postgres(at)gmail(dot)com> |
| Subject: | Re: pg15: reltuples stuck at -1 after pg_upgrade and VACUUM |
| Date: | 2023-08-09 15:41:21 |
| Message-ID: | CAH2-Wzm=UwJjO+KgoBu6p1ibn0Bu2_rRNvZk_7fqqE6Z3m3+vQ@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Wed, Aug 9, 2023 at 6:18 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)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
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