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In-Reply-To: <aPBsd2e2SqLs0Kdk@paquier.xyz>
From: Pavel Stehule <pavel.stehule@gmail.com>
Date: Sun, 14 Dec 2025 08:40:20 +0100
Message-ID: 
 <CAFj8pRB_FH-Pcth9XFcpY2OTasVOP-2DfYOsVxL38igw0O4hdg@mail.gmail.com>
Subject: Re: [PROPOSAL] Termination of Background Workers for ALTER/DROP
 DATABASE
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>
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Hi

ne 14. 12. 2025 v 8:26 odes=C3=ADlatel 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

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<div dir=3D"ltr"><div>Hi</div><br><div class=3D"gmail_quote gmail_quote_con=
tainer"><div dir=3D"ltr" class=3D"gmail_attr">ne 14. 12. 2025 v=C2=A08:26 o=
des=C3=ADlatel Michael Paquier &lt;<a href=3D"mailto:michael@paquier.xyz">m=
ichael@paquier.xyz</a>&gt; napsal:<br></div><blockquote class=3D"gmail_quot=
e" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204)=
;padding-left:1ex">On Wed, Oct 15, 2025 at 02:48:43AM +0000, Aya Iwata (Fuj=
itsu) wrote:<br>
&gt; Thank you for your comments. I updated this patch to v0007.<br>
<br>
+ * Exit the bgworker when its database is dropped, renamed, moved to a<br>
+ * different tablespace, or used as a template for CREATE DATABASE.<br>
<br>
I don&#39;t think that we need to list all these operations in details<br>
here. We could just say &quot;if its database is involved in a CREATE,<br>
ALTER or DROP database command&quot;.=C2=A0 The docs should provide these<b=
r>
details, of course.<br>
<br>
+#define BGWORKER_EXIT_AT_DATABASE_CHANGE=C2=A0 =C2=A0 =C2=A0 =C2=A00x0004 =
<br>
<br></blockquote><div><br></div>I am checking this patch, and I think so us=
ed names can be little bit confusing</div><div class=3D"gmail_quote gmail_q=
uote_container"><br></div><div class=3D"gmail_quote gmail_quote_container">=
BGWORKER_EXIT_AT_DATABASE_CHANGE - it is used for disconnecting workers on =
the template database, and this database is not changing.</div><div class=
=3D"gmail_quote gmail_quote_container"><br></div><div>TerminateBgWorkersByD=
bOid - it doesn&#39;t terminate all workers, but only workers with some spe=
cial flags</div><div><br></div><div>Maybe BGWORKER_INTERRUPTABLE and=C2=A0T=
erminateInterruptableBgWorkersByDbOid ?</div><div><br></div><div>Another qu=
estion is if this cancellation should be implicit and should not require so=
me special flag.</div><div><br></div><div>When I want to disconnect connect=
ions to database when I do drop, I have to use FORCE flag</div><div><br></d=
iv><div>So maybe there should be ALTER DATABASE ... RENAME ... FORCE - or i=
f FORCE can terminare all workers (without special FLAG) ?</div><div><br></=
div><div>Regards</div><div><br></div><div>Pavel</div><div><br></div><div><b=
r></div><div><br></div><div><br></div></div>

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