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From: Kirill Reshke <reshkekirill@gmail.com>
Date: Sat, 23 May 2026 15:14:42 +0500
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Subject: Re: Pg upgrade bug with NOT NULL NOT VALID
To: =?UTF-8?Q?=C3=81lvaro_Herrera?= <alvherre@kurilemu.de>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Thu, 21 May 2026 at 22:18, =C3=81lvaro Herrera <alvherre@kurilemu.de> wr=
ote:
>
> Hi,
>

Hi, thank you for looking into this.

> I see two alternatives.  One is to have pg_dump --binary-upgrade choose
> a constraint name for the not-null with full knowledge of all other
> constraint names, so that we know to generate a non conflicting one.
> I suspect this is not easy to code.
>

Well, for this option, we need to be told about what other constraint
names that are about to be created. So, pg_dump will need to issue an
SQL that says: please create this relation, but also never choose
name1 to anything in the process. I guess this is not committable...
Maybe you can clarify the design here?

> The other is much simpler: make pg_upgrade -c warn you about the check
> constraint name so that you know to rename it before the upgrade.

I don't think this is good when the database asks you to change your
DDL because of its internal troubles with something.

I also think we should make pg_upgrade just work in this case.


--=20
Best regards,
Kirill Reshke