Re: Allow to collect statistics on virtual generated columns

Yugo Nagata <nagata@sraoss.co.jp>

From: Yugo Nagata <nagata@sraoss.co.jp>
To: Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers@postgresql.org
Date: 2026-03-24T14:01:10Z
Lists: pgsql-hackers
On Tue, 24 Mar 2026 11:43:47 +0000
Dean Rasheed <dean.a.rasheed@gmail.com> wrote:

> On Tue, 24 Mar 2026 at 10:57, Yugo Nagata <nagata@sraoss.co.jp> wrote:
> >
> > One concern is that CREATE STATISTICS does not allow creating extended
> > statistics on a single colmun. If we try this, it raises the following error:
> >
> >  ERROR:  extended statistics require at least 2 columns
> >
> > Therefore, if we take this approach, we would need to add an exception
> > to this rule for virtual columns.
> 
> I think that would be fine. It makes sense because a virtual column
> expands to an expression, and we already allow CREATE STATISTICS on a
> single expression.

I see, that makes sense. I'll update the patch accordingly.

Regards,
Yugo Nagata

> 
> Regards,
> Dean


-- 
Yugo Nagata <nagata@sraoss.co.jp>



Commits

  1. Add support for extended statistics on virtual generated columns.