Horton

Re: logical decoding and replication of sequences, take 2

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Tomas Vondra <tomas.vondra@enterprisedb.com>
Cc: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Masahiko Sawada <sawada.mshk@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Date: 2023-10-14T11:53:18Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Migrate logical slots to the new node during an upgrade.

  2. Make test_decoding ddl.out shorter

  3. Fix snapshot handling in logicalmsg_decode

  4. doc: Adjust a few more references to "postmaster"

  5. Revert "Logical decoding of sequences"

On Thu, Oct 12, 2023 at 9:03 PM Tomas Vondra
<tomas.vondra@enterprisedb.com> wrote:
>
> On 7/25/23 12:20, Amit Kapila wrote:
> > ...
> >
> > I have used the debugger to reproduce this as it needs quite some
> > coordination. I just wanted to see if the sequence can go backward and
> > didn't catch up completely before the sequence state is marked
> > 'ready'. On the publisher side, I created a publication with a table
> > and a sequence. Then did the following steps:
> > SELECT nextval('s') FROM generate_series(1,50);
> > insert into t1 values(1);
> > SELECT nextval('s') FROM generate_series(51,150);
> >
> > Then on the subscriber side with some debugging aid, I could find the
> > values in the sequence shown in the previous email. Sorry, I haven't
> > recorded each and every step but, if you think it helps, I can again
> > try to reproduce it and share the steps.
> >
>
> Amit, can you try to reproduce this backwards movement with the latest
> version of the patch?
>

I lost touch with this patch but IIRC the quoted problem per se
shouldn't occur after the idea to use page LSN instead of slot's LSN
for synchronization between sync and apply worker.

-- 
With Regards,
Amit Kapila.