Re: Logical Replication of sequences

From: shveta malik <shveta(dot)malik(at)gmail(dot)com>
To: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
Cc: Dilip Kumar <dilipbalaut(at)gmail(dot)com>, vignesh C <vignesh21(at)gmail(dot)com>, Shlok Kyal <shlok(dot)kyal(dot)oss(at)gmail(dot)com>, Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, "Hayato Kuroda (Fujitsu)" <kuroda(dot)hayato(at)fujitsu(dot)com>, Nisha Moond <nisha(dot)moond412(at)gmail(dot)com>, Peter Smith <smithpb2250(at)gmail(dot)com>, Peter Eisentraut <peter(at)eisentraut(dot)org>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Euler Taveira <euler(at)eulerto(dot)com>, Michael Paquier <michael(at)paquier(dot)xyz>, "Zhijie Hou (Fujitsu)" <houzj(dot)fnst(at)fujitsu(dot)com>, "Jonathan S(dot) Katz" <jkatz(at)postgresql(dot)org>, shveta malik <shveta(dot)malik(at)gmail(dot)com>
Subject: Re: Logical Replication of sequences
Date: 2025-10-09 06:32:20
Message-ID: CAJpy0uAXYWFMh4jnR=quabmn9C=iNd=dRmQur7Z1Ujfuot=tKA@mail.gmail.com
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On Thu, Oct 9, 2025 at 11:32 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Thu, Oct 9, 2025 at 11:27 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> >
> > On Thu, Oct 9, 2025 at 10:14 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > > On Wed, Oct 8, 2025 at 9:13 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> > > >
> > > > On Tue, Oct 7, 2025 at 5:46 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > > > >
> > > >
> > > > > > I have one more question: while testing the sequence sync, I found
> > > > > > this behavior is documented as well[1], but what's the reasoning
> > > > > > behind it? Why REFRESH PUBLICATION will synchronize only newly added
> > > > > > sequences and need to use REFRESH PUBLICATION SEQUENCES to
> > > > > > re-synchronize all sequences.
> > > > > >
> > > > >
> > > > > The idea is that REFRESH PUBLICATION should behave similarly for
> > > > > tables and sequences. This means that this command is primarily used
> > > > > to add/remove tables/sequences and copy their respective initial
> > > > > contents. The new command REFRESH PUBLICATION SEQUENCES is to sync the
> > > > > existing sequences, it shouldn't add any new sequences, now, if it is
> > > > > too confusing we can discuss having a different syntax for it.
> > > >
> > > > Sure, let's discuss this when we get this patch at the start of the
> > > > commit queue.
> > > >
> > >
> > > I have pushed the publications related patch. Now, we can discuss this
> > > command. I think confusion arises from the fact that both commands use
> > > REFRESH.
> >
> > Right
> >
> > So, how about for the second case (sync/copy all existing
> > > sequences), we use a different command, some ideas that come to my
> > > mind are:
> > >
> > > Alter Subscription sub1 REPLICATE Publication Sequences;
> > > Alter Subscription sub1 RESYNC Publication Sequences;
> > > Alter Subscription sub1 SYNC Publication Sequences;
> > > Alter Subscription sub1 MERGE Publication Sequences;
> > >
> > > Among these, the first three require a new keyword to be introduced. I
> > > prefer to use existing keyword if possible. Any ideas?
> >
> > I would have preferred "Alter Subscription sub1 SYNC Publication
> > Sequences" but if your preference is to use existing keywords then
> > IMHO "MERGE Publication Sequences" or "UPDATE Publication Sequences"
> > are also good options.
> >
>
> I would prefer "COPY Publication Sequences" or "UPDATE Publication
> Sequences" among the given options. We have a precedence for copy
> (copy_data) in publication command parameters, so, COPY could be a
> better option.
>

If not SYNC, then COPY looks the next best option to me.

thanks
Shveta

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