Re: [PATCH] Support automatic sequence replication

On Tue, Feb 24, 2026 at 4:07 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Mon, Feb 23, 2026 at 11:14 AM Hayato Kuroda (Fujitsu)
> <kuroda(dot)hayato(at)fujitsu(dot)com> wrote:
> >
> > Dear Dilip,
> >
> > > Thanks for clarifying the use case, and I agree this is a valid use
> > > case, although I am not completely sure how exactly we are achieving
> > > that? I mean sequence sync workers need to fetch the list of all
> > > published sequences to identify whether they are in sync with the
> > > local sequence state or not? Or somehow we can avoid that? If not
> > > what we would save, updating the local states of the sequences if they
> > > are already in sync?
> >
> > IIUC, the sequencesync worker first lists all sequences on the subscriber, then
> > gets their states on the publisher side. Then the worker updates the state only
> > when the sequence between instances is different.
> >
> > Does it make sense for you?
>
> Thanks, yeah that absolutely makes sense, one of the key requirement
> while using the logical replication for the major version upgrade is
> how long is the downtime before switchover and thats directly
> proportional to the time we take in syncing. So with automatic
> sequence sync if we are ensuring that only the sequences which were
> not synced automatically are synced with REFRESH that then this would
> be very good feature addition. However, I will look into the patch to
> see how we are taking care of syncing the sequences which are not
> already synced.
>

This is done by comparing local and remote sequence values.

Have we done any time measurement with very large
> number of sequences, that how much time REFRESH SEQUENCES takes with
> or without patch?

Even if done, nothing is shared on -hackers. So, we should do some
measurement in this regard, if not done already, and share the data.

--
With Regards,
Amit Kapila.