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Date: Tue, 25 Aug 2026 18:13:05 +0200
Message-Id: <DKY5OJ1NSSGO.3U2FKRKCHM533@gmail.com>
To: "Laurenz Albe" <laurenz.albe@cybertec.at>, "Alberto Piai"
 <alberto.piai@gmail.com>, <pgsql-hackers@postgresql.org>
Subject: Re: Adding a stored generated column without long-lived locks
Cc: =?utf-8?q?=C3=81lvaro_Herrera?= <alvherre@kurilemu.de>
From: "Alberto Piai" <alberto.piai@gmail.com>
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On Tue Aug 25, 2026 at 10:46 AM CEST, Laurenz Albe wrote:
> On Mon, 2026-08-24 at 22:03 +0200, Alberto Piai wrote:
>> > I was wondering about this hint:
>> >=20
>> > =C2=A0=C2=A0 Use this command on the root table/partition without ONLY=
.
>> >=20
>> > You can never turn a column of a partition into a generated column, ri=
ght?
>> > How about
>> >=20
>> > =C2=A0=C2=A0 Use the command on the partition root without specifying =
ONLY.
>>=20
>> Since this is also taking care of classic inheritance, it seems strange
>> to only mention partitions. But I see that this way it's confusing (and
>> I do concede that partitioning might be the more widely used of the two)
>> so I switched it around to "on the root partition/table without
>> specifying ONLY". Does that make more sense?
>
> My problem is that there is no "root partition".

Ah, I see what you mean now. I agree, "root partition" makes no sense.

So, removing the slash, it would look like:

  ERROR:  cannot convert column "c" to generated
  DETAIL:  Converting only part of a partitioning or inheritance hierarchy =
is not supported.
  HINT:  Use this command on the partitioning or inheritance root without s=
pecifying ONLY.

Maybe a bit heavy on the eye?

Since the root of the hierarchy is in both cases just a table
(partitoned or not), what about just calling it a table?

  ERROR:  cannot convert column "c" to generated
  DETAIL:  Converting only part of a partitioning or inheritance hierarchy =
is not supported.
  HINT:  Use this command on the root table without specifying ONLY.


Regards,

Alberto


--=20
Alberto Piai
Sensational AG
Z=C3=BCrich, Switzerland