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From: Amit Kapila <amit.kapila16@gmail.com>
Date: Thu, 2 Apr 2026 12:04:18 +0530
Message-ID: 
 <CAA4eK1JwVewYZc7eyF9x2-G+Y1ikgU5+a5gmQR+ssft++V51ZA@mail.gmail.com>
Subject: Re: Use SIGTERM instead of SIGUSR1 for slotsync worker to exit during
 promotion?
To: Fujii Masao <masao.fujii@gmail.com>
Cc: Nisha Moond <nisha.moond412@gmail.com>,
	"Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>,
 shveta malik <shveta.malik@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Thu, Apr 2, 2026 at 10:31=E2=80=AFAM Fujii Masao <masao.fujii@gmail.com>=
 wrote:
>
> On Wed, Apr 1, 2026 at 8:11=E2=80=AFPM Nisha Moond <nisha.moond412@gmail.=
com> wrote:
> > > As for backpatching, this looks like it should go back to v17, where =
slotsync
> > > was introduced. Thought?
> >
> > Right, the issue exists in v17 as well.
> >
> > Attached the updated patch.
>
> Thanks for updating the patch! LGTM.
>
> I noticed that commit 1362bc33e02 updated the slotsync code so that a bac=
kend
> performing slot synchronization is signaled on promotion, but it was appl=
ied
> only to master. I=E2=80=99m not sure why it wasn=E2=80=99t backpatched to=
 v17 and v18,
>

It is because we added retry slot-sync logic for API in master in
commit 0d2d4a0ec3eca64e7f5ce7f7630b56a561b2663c. So, there is no
chance of API waiting except for the race condition being discussed
here.

> but it seems we need to backpatch it first before backpatching this patch=
.
> Thought?
>

I feel the use of API before this version was mainly for test-cases as
it was not production ready. So, it is less helpful to backpatch
1362bc33e02, if we want, we can backpatch only the worker part of the
fix. OTOH, as the issue is not frequent and we have some workaround
(at least for more common platforms) as well, we can consider not
backpatching it.

--=20
With Regards,
Amit Kapila.