Re: regarding statistics retaining with 18 Upgrade

From: Robert Treat <rob(at)xzilla(dot)net>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: Rambabu V <ram(dot)wissen(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: regarding statistics retaining with 18 Upgrade
Date: 2025-11-15 23:52:15
Message-ID: CABV9wwO8nZ8UXQP0+sDSvM9D8uOsmCpyXgtqS=fCFz1YeXB8KA@mail.gmail.com
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On Sat, Nov 15, 2025 at 9:32 AM Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> On Sat, Nov 15, 2025 at 06:02:53PM +0800, Rambabu V wrote:
> > Hi Team,
> >
> > seems stats are not retained after upgrade. Below are the artifacts , is it
> > expected? as per the release notes statistics should be retained.
>
> Uh, it is the _optimizer_ statistics that are preserved by pg_upgrade,
> not the cumulative statistics system:
>
> https://www.postgresql.org/docs/current/monitoring-stats.html
>
> Yes, they are easily confused.
>

I wonder if it might be worth trying to clarify this a little bit
more... perhaps something like the attached?

Robert Treat
https://xzilla.net

Attachment Content-Type Size
v1-0001-Clarify-statistics-dumped-by-statistics.patch application/octet-stream 4.1 KB

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