Re: [PROPOSAL] Termination of Background Workers for ALTER/DROP DATABASE

Pavel Stehule <pavel.stehule@gmail.com>

From: Pavel Stehule <pavel.stehule@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: "Aya Iwata (Fujitsu)" <iwata.aya@fujitsu.com>, Peter Smith <smithpb2250@gmail.com>, Chao Li <li.evan.chao@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2025-12-14T07:40:20Z
Lists: pgsql-hackers
Hi

ne 14. 12. 2025 v 8:26 odesílatel Michael Paquier <michael@paquier.xyz>
napsal:

> On Wed, Oct 15, 2025 at 02:48:43AM +0000, Aya Iwata (Fujitsu) wrote:
> > Thank you for your comments. I updated this patch to v0007.
>
> + * Exit the bgworker when its database is dropped, renamed, moved to a
> + * different tablespace, or used as a template for CREATE DATABASE.
>
> I don't think that we need to list all these operations in details
> here. We could just say "if its database is involved in a CREATE,
> ALTER or DROP database command".  The docs should provide these
> details, of course.
>
> +#define BGWORKER_EXIT_AT_DATABASE_CHANGE       0x0004
>
>
I am checking this patch, and I think so used names can be little bit
confusing

BGWORKER_EXIT_AT_DATABASE_CHANGE - it is used for disconnecting workers on
the template database, and this database is not changing.

TerminateBgWorkersByDbOid - it doesn't terminate all workers, but only
workers with some special flags

Maybe BGWORKER_INTERRUPTABLE and TerminateInterruptableBgWorkersByDbOid ?

Another question is if this cancellation should be implicit and should not
require some special flag.

When I want to disconnect connections to database when I do drop, I have to
use FORCE flag

So maybe there should be ALTER DATABASE ... RENAME ... FORCE - or if FORCE
can terminare all workers (without special FLAG) ?

Regards

Pavel