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: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, 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>, Dilip Kumar <dilipbalaut@gmail.com>
Date: 2023-12-06T10:19:29Z
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 Sun, Dec 3, 2023 at 11:56 PM Tomas Vondra
<tomas.vondra@enterprisedb.com> wrote:
>
> On 12/3/23 18:52, Tomas Vondra wrote:
> > ...
> >
>
> Another idea is that maybe we could somehow inform ReorderBuffer whether
> the output plugin even is interested in sequences. That'd help with
> cases where we don't even want/need to replicate sequences, e.g. because
> the publication does not specify (publish=sequence).
>
> What happens now in that case is we call ReorderBufferQueueSequence(),
> it does the whole dance with starting/aborting the transaction, calls
> rb->sequence() which just does "meh" and doesn't do anything. Maybe we
> could just short-circuit this by asking the output plugin somehow.
>
> In an extreme case the plugin may not even specify the sequence
> callbacks, and we're still doing all of this.
>

We could explore this but I guess it won't solve the problem we are
facing in cases where all sequences are published and plugin has
specified the sequence callbacks. I think it would add some overhead
of this check in positive cases where we decide to anyway do send the
changes.

-- 
With Regards,
Amit Kapila.