Feedback-ID: id4a34324:Fastmail
Date: Mon, 8 Jun 2026 09:01:24 -0400
From: Andres Freund <andres@anarazel.de>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Chao Li <li.evan.chao@gmail.com>,
	Postgres hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Fix tuple deformation with virtual generated NOT NULL columns
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Hi,

On 2026-06-06 16:50:29 +1200, David Rowley wrote:
> On Thu, 4 Jun 2026 at 17:57, Chao Li <li.evan.chao@gmail.com> wrote:
> > While testing "Optimize tuple deformation”, I found a bug:
> 
> > I think the problem is in finding the first non-guaranteed attribute where virtual generated attributes are not considered:
> 
> Thanks for the report and fix. I pushed a slightly adjusted version.
> Form_pg_attribute.attgenerated is '\0' for non-generated columns, so
> there's no point in checking cattr->attgenerated as well as that.
> 
> I also added an Assert() to help catch any other reason that the
> guaranteed column gets set incorrectly again in TupleDescFinalize().

Seems like a test for some of this would be good too?

Greetings,

Andres Freund