Re: FOR PORTION OF should reject GENERATED columns

From: Paul A Jungwirth <pj(at)illuminatedcomputing(dot)com>
To: Peter Eisentraut <peter(at)eisentraut(dot)org>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: FOR PORTION OF should reject GENERATED columns
Date: 2026-06-29 06:29:12
Message-ID: CA+renyVec2yhFXWkNN178-qN4s5BAY6WFqq66ou3bHxSzUkArQ@mail.gmail.com
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On Sat, Jun 27, 2026 at 12:05 AM Peter Eisentraut <peter(at)eisentraut(dot)org> wrote:
>
> > The test about BEGIN ATOMIC functions now shows that the analysis-time
> > check prevents you from defining the function.
>
> Hmm, I think doing it in the parser won't actually work if you are
> writing through a view. For example, with the v4 patch, the following
> does not error:
>
> CREATE TABLE t (a int, b int4range GENERATED ALWAYS AS (int4range(a, a +
> 1)) STORED);
> CREATE VIEW v AS SELECT * FROM t;
> DELETE FROM v FOR PORTION OF b FROM 1 TO 2;
>
> So we need to push it later after all.
>
> But maybe it would fit in the planner, near where the volatility check
> is being moved to?

That's a good catch. Here is a version that checks in the planner,
with your example added to the test cases. This is a little nicer than
the executor, since rangeVar hasn't been converted to an expression
yet (for VIRTUAL columns).

Yours,

--
Paul ~{:-)
pj(at)illuminatedcomputing(dot)com

Attachment Content-Type Size
v5-0001-Forbid-GENERATED-columns-in-FOR-PORTION-OF.patch text/x-patch 8.7 KB

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