Horton

Re: Logical Replication of sequences

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: Peter Smith <smithpb2250@gmail.com>
Cc: Chao Li <li.evan.chao@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, Dilip Kumar <dilipbalaut@gmail.com>, shveta malik <shveta.malik@gmail.com>, Shlok Kyal <shlok.kyal.oss@gmail.com>, Nisha Moond <nisha.moond412@gmail.com>, Peter Eisentraut <peter@eisentraut.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Euler Taveira <euler@eulerto.com>, Michael Paquier <michael@paquier.xyz>, "Jonathan S. Katz" <jkatz@postgresql.org>
Date: 2025-10-29T16:13:18Z
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. Doc: Add documentation for sequence synchronization.

  2. Remove unused assignment in CREATE PUBLICATION grammar.

  3. Add seq_sync_error_count to subscription statistics.

  4. Fix few issues in commit 5509055d69.

  5. Add sequence synchronization for logical replication.

  6. Add worker type argument to logical replication worker functions.

  7. Introduce "REFRESH SEQUENCES" for subscriptions.

  8. Refactor logical worker synchronization code into a separate file.

  9. Standardize use of REFRESH PUBLICATION in code and messages.

  10. Add "ALL SEQUENCES" support to publications.

  11. Expose sequence page LSN via pg_get_sequence_data.

  12. Resume conflict-relevant data retention automatically.

  13. Post-commit review fixes for 228c370868.

  14. Generate GUC tables from .dat file

On Wed, 29 Oct 2025 at 09:19, Peter Smith <smithpb2250@gmail.com> wrote:
>
> Hi Vignesh,
>
> Some review comments patch V20251029-0001 (the test code only)
>
> ======
> src/test/subscription/t/036_sequences.pl
>
> 1.
> +##########
> +## ALTER SUBSCRIPTION ... REFRESH PUBLICATION with (copy_data = off) should
> +# not update the sequence values for the new sequence.
> +##########
> +
> +# Create a new sequence 'regress_s4'
> +$node_publisher->safe_psql(
> + 'postgres', qq(
> + CREATE SEQUENCE regress_s4;
> + INSERT INTO regress_seq_test SELECT nextval('regress_s4') FROM
> generate_series(1,100);
> +));
> +
>
> AFAICT the sequence `regress_s3` (from the previous test part) was
> already a "new sequence" that had not yet been REFRESHED to the
> subscriber. So I think maybe there wasn't any need to create another
> sequence `regress_s4` for this test part.

Modified

> ~~~
>
> 2.
> +# Check - newly published sequence values are not updated
> +$result = $node_subscriber->safe_psql(
> + 'postgres', qq(
> + SELECT last_value, log_cnt, is_called FROM regress_s4;
> +));
>
> Maybe that comment can give more details:
> # Check - newly published sequence values are not updated when (copy_data = off)

Modified

> ~~~
>
> 3.
> +##########
> +# ALTER SUBSCRIPTION ... REFRESH PUBLICATION should report an error when:
> +# a) sequence definitions differ between the publisher and subscriber, or
> +# b) a sequence is missing on the publisher.
> +##########
>
> OK, you have these mismatch parameters and missing sequences test for
> "REFRESH PUBLICATION", but what about doing the same tests for
> "REFRESH SEQUENCES" -- e,g, I am thinking you can ALTER/DROP some
> publication that previously had synchronized OK, to verify what
> happens during "REFRESH SEQUENCES".

I'm planning to do this in a later version.

The changes for the same are available in the v20251029_2 version
patch attached at [1].
[1] - https://www.postgresql.org/message-id/CALDaNm18siwD6Mamv8Dd8ubwSCw3Fi6SnB4B3Lr%2B4R7snLkfeA%40mail.gmail.com

Regards,
Vignesh