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From: John Naylor <johncnaylorls@gmail.com>
Date: Thu, 26 Mar 2026 16:22:07 +0700
Message-ID: 
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Subject: Re: Adjust error message for CREATE STATISTICS to account for
 expressions
To: Yugo Nagata <nagata@sraoss.co.jp>
Cc: Pgsql Hackers <pgsql-hackers@postgresql.org>
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On Wed, Mar 25, 2026 at 11:15=E2=80=AFAM Yugo Nagata <nagata@sraoss.co.jp> =
wrote:
>
> On Wed, 25 Mar 2026 08:24:40 +0700
> John Naylor <johncnaylorls@gmail.com> wrote:

> > I'm ambivalent about this. Instead of trying to document all the
> > possible valid possibilities (which may get out of date again), maybe
> > we can say that it's not allowed on a single column?
>
> Thank you for the suggestion. I agree that this is a simpler approach,
> so I've attached a revised patch.

- errmsg("extended statistics require at least 2 columns")));
+ errmsg("extended statistics are not supported on a single column")));

I'd probably write this as "extended statistics on a single column are
not supported" (no need to send a new patch).

Any objections?

Also, I'm leaning towards not backpatching -- I figure a user that got
here by fat-fingering an expression is not likely to be too confused.

I looked in the feature thread and saw that this was actually raised
during development of the feature:

https://www.postgresql.org/message-id/CAEZATCU9uPo7JYdx4k0-ufXXZH8t7itodibU=
wCva%2Bs%2BAvAKcnw%40mail.gmail.com

--=20
John Naylor
Amazon Web Services