Re: Fix tuple deformation with virtual generated NOT NULL columns

David Rowley <dgrowleyml@gmail.com>

From: David Rowley <dgrowleyml@gmail.com>

To: Chao Li <li.evan.chao@gmail.com>

Cc: Postgres hackers <pgsql-hackers@lists.postgresql.org>

Date: 2026-06-06T04:50:29Z

Lists: pgsql-hackers

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().

David

Commits

Update JIT tuple deforming code for virtual generated columns
- e9692de1d6f6 18 (unreleased) landed
- dc5116780846 19 (unreleased) landed
Add tuple deformation test for virtual generated columns
- 1f7dfe8c8ef7 19 (unreleased) landed
Fix tuple deforming with virtual generated columns
- 89eafad297a9 19 (unreleased) landed