Re: Logical Replication of sequences

vignesh C <vignesh21@gmail.com>

From: vignesh C <vignesh21@gmail.com>

To: Dilip Kumar <dilipbalaut@gmail.com>

Cc: shveta malik <shveta.malik@gmail.com>, Nisha Moond <nisha.moond412@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Peter Smith <smithpb2250@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Shlok Kyal <shlok.kyal.oss@gmail.com>, Peter Eisentraut <peter@eisentraut.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Euler Taveira <euler@eulerto.com>, Michael Paquier <michael@paquier.xyz>, "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, "Jonathan S. Katz" <jkatz@postgresql.org>

Date: 2025-07-21T09:06:32Z

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 →

Doc: Add documentation for sequence synchronization.
- 55cefadde874 19 (unreleased) landed
Remove unused assignment in CREATE PUBLICATION grammar.
- bfb7419b0bbe 19 (unreleased) landed
Add seq_sync_error_count to subscription statistics.
- f6a4c498dcf6 19 (unreleased) landed
Fix few issues in commit 5509055d69.
- 5a4eba558aa7 19 (unreleased) landed
Add sequence synchronization for logical replication.
- 5509055d6956 19 (unreleased) landed
Add worker type argument to logical replication worker functions.
- 3e8e05596a02 19 (unreleased) landed
Introduce "REFRESH SEQUENCES" for subscriptions.
- f0b3573c3aac 19 (unreleased) landed
Refactor logical worker synchronization code into a separate file.
- 41c674d2e31e 19 (unreleased) landed
Standardize use of REFRESH PUBLICATION in code and messages.
- 2436b8c047ff 19 (unreleased) landed
Add "ALL SEQUENCES" support to publications.
- 96b378497346 19 (unreleased) landed
Expose sequence page LSN via pg_get_sequence_data.
- b93172ca59f4 19 (unreleased) landed
Resume conflict-relevant data retention automatically.
- 0d48d393d465 19 (unreleased) cited
Post-commit review fixes for 228c370868.
- 1f7e9ba3ac4e 19 (unreleased) cited
Generate GUC tables from .dat file
- 63599896545c 19 (unreleased) cited

On Mon, 21 Jul 2025 at 11:15, Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Mon, Jul 21, 2025 at 10:36 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> >
> > I was just trying a different test, so I realized that ALTER
> > PUBLICATION ADD SEQUENCE is not supported, any reason for the same?
> >
> > postgres[154731]=# ALTER PUBLICATION pub ADD sequence s1;
> > ERROR:  42601: invalid publication object list
> > LINE 1: ALTER PUBLICATION pub ADD sequence s1;
> > DETAIL:  One of TABLE or TABLES IN SCHEMA must be specified before a
> > standalone table or schema name.
> > LOCATION:  preprocess_pubobj_list, gram.y:19685
> >
> Also I noticed that
> 1. We don't allow creating publication with individual sequences (e.g.
> CREATE PUBLICATION pub FOR SEQUENCE s1;).  Is it because the main
> purpose of this sync is major version upgrade and we do not have
> scenarios for replicating a few sequences or there are some technical
> difficulties in achieving that or both.

There are no technical difficulties here. The main goal was to support
all sequences necessary for the upgrade scenario. Once that is
complete, the implementation can be extended based on additional use
cases.

> 2. This syntax works (CREATE PUBLICATION pub FOR ALL TABLES,
> SEQUENCES;) but tab completion doesn't suggest this

Nisha had analysed this and shared this  earlier at [1]:
Tab-completion is not supported after a comma (,) in any other cases.
For example, the following commands are valid, but tab-completion does
not work after the comma:
CREATE PUBLICATION pub7 FOR TABLE t1, TABLES IN SCHEMA public;
CREATE PUBLICATION pub7 FOR TABLES IN SCHEMA public, TABLES IN SCHEMA schema2;

> 3. Some of the syntaxes works for sequence which doesn't make sense to
> me, as listed below, I think there are more
>
> postgres[154731]=# CREATE PUBLICATION insert_only FOR ALL SEQUENCES
> WITH (publish = 'insert');
> CREATE PUBLICATION
>
> postgres[154731]=# CREATE PUBLICATION pub FOR ALL SEQUENCES WITH (
> PUBLISH_VIA_PARTITION_ROOT );
> CREATE PUBLICATION

There is a documentation for this at sql-createpublication.html:
WITH ( publication_parameter [= value] [, ... ] )
    This clause specifies optional parameters for a publication when
publishing tables. This clause is not applicable for sequences.

I felt it was enough, should we do anything more here?

[1] - https://www.postgresql.org/message-id/CABdArM5axwoTorZnJww5rE79SNzvnnXCfWkv7XJex1Rkz%3DJDog%40mail.gmail.com

Regards,
Vignesh