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From: Amit Kapila <amit.kapila16@gmail.com>
Date: Sat, 21 Mar 2026 22:22:31 +0530
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 <CAA4eK1+CrQNqiPDKv1wYfdkbX0FARJoi1=0ioaAqkLzbq2vG1w@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: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Wed, Mar 18, 2026 at 9:35=E2=80=AFPM Fujii Masao <masao.fujii@gmail.com>=
 wrote:
>
> I noticed that during standby promotion the startup process sends SIGUSR1=
 to
> the slotsync worker to make it exit. Is there a reason for using SIGUSR1?
>

IIRC, this same signal is used for both the backend executing
pg_sync_replication_slots() and slotsync worker. We want the worker to
exit and error_out backend. Using SIGTERM for backend could result in
its exit. Also, we want the last slotsync cycle to complete before
promotion so that chances of subscribers that do failover/switchover
to new primary has better chances of finding failover slots
sync-ready.

--=20
With Regards,
Amit Kapila.