Re: Logical Replication of sequences

On Mon, 8 Sept 2025 at 12:05, Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com> wrote:
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> On Sep 8, 2025, at 14:00, vignesh C <vignesh21(at)gmail(dot)com> wrote:
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> 1 - 0001
> ```
> diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
> index 2c220b60749..c8adddbfa31 100644
> --- a/src/test/regress/sql/sequence.sql
> +++ b/src/test/regress/sql/sequence.sql
> @@ -414,6 +414,6 @@ SELECT nextval('test_seq1');
> SELECT nextval('test_seq1');
>
> -- pg_get_sequence_data
> -SELECT * FROM pg_get_sequence_data('test_seq1');
> +SELECT last_value, is_called, log_cnt, page_lsn <= pg_current_wal_lsn() as lsn FROM pg_get_sequence_data('test_seq1');
>
> DROP SEQUENCE test_seq1;
> ```
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> As it shows log_cnt now, after calling pg_get_sequence_data(), I suggest add 8 nextval(), so that sequence goes to 11, and log_cnt should become to 22.
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> Could you please explain the reason you’d like this to be done?
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> Because log_cnt is newly exposed, we want to verify its value in the test. When I first time ran the test code, I saw initial value of log_cnt was 32, then I thought log_cnt might get decreased if I ran nextval() again, but it didn’t. Only after I ran 10 (cache size) more nextval(), log_cnt got decreased by 10 to 22. The test code is a place for people to look for expected behavior. So I think adding more nextval() to verify and show the change of log_cnt is helpful.

This is addressed in the attached patch, also rebased the patch
because of recent commits.

Regards,
Vignesh