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From: Amit Kapila <amit.kapila16@gmail.com>
Date: Tue, 24 Feb 2026 16:55:20 +0530
Message-ID: <CAA4eK1J6zwM1WOnhHR7VYNMAmGiQKf9=KL+Vz+BM3=QuhtL_Lw@mail.gmail.com>
Subject: Re: [PATCH] Support automatic sequence replication
To: Ajin Cherian <itsajin@gmail.com>
Cc: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, shveta malik <shveta.malik@gmail.com>, 
	Ashutosh Sharma <ashu.coek88@gmail.com>, 
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Tue, Feb 24, 2026 at 4:34=E2=80=AFPM Ajin Cherian <itsajin@gmail.com> wr=
ote:
>
> Currently REFRESH SEQUENCES can only be called if the subscription is
> enabled. All it does is change the states of all the sequences in
> subscription_rel to INIT, this will prompt the sequence worker to wake
> up and unconditionally sync all the sequences. For sequences in the
> INIT state, it doesn't check if there is drift or not, it updates all
> sequences unconditionally. From your discussions with Dilip, I
> understand we want to reduce the time it takes to REFRESH SEQUENCES at
> the time of an upgrade. If so, then this might not be a good approach.
>

The point I was trying to make is that with automatic sequence sync,
we won't need to execute REFRESH SEQUENCES before upgrade or failover
as the sequences will be in sync.

> As not only does the sequence worker have to update all sequences even
> if they have not drifted, it also has to update the relstate of all
> these sequences to READY. I propose, we change the logic such that
> REFRESH SEQUENCES only wakes up the sequence worker, that will reduce
> the time as most sequences will already be in READY state (unless
> newly added) and only sequences that have not drifted need to be
> updated and no catalog update is required for sequence states already
> in READY state. One downside to this is that, earlier users could
> issue a REFRESH SEQUENCES and wait to see if all the sequences have
> returned to the READY state to confirm that the sync has completed,
> with this approach that advantage is not there. Users might have to
> use a query to find the sequence values of all the sequences and
> compare that with the values in the publisher.
>

Yeah, this point needs more thoughts as the existing method for
REFRESH SEQUENCES also allows users to easily verify if the sequences
are in sync.

--=20
With Regards,
Amit Kapila.