Re: Logical Replication of sequences

On Thu, 25 Jul 2024 at 12:08, shveta malik <shveta(dot)malik(at)gmail(dot)com> wrote:
>
> On Thu, Jul 25, 2024 at 9:06 AM vignesh C <vignesh21(at)gmail(dot)com> wrote:
> >
> > The attached v20240725 version patch has the changes for the same.
>
> Thank You for addressing the comments. Please review below issues:
>
> 1) Sub ahead of pub due to wrong initial sync of last_value for
> non-incremented sequences. Steps at [1]
> 2) Sequence's min value is not honored on sub during replication. Steps at [2]
>
> [1]:
> -----------
> on PUB:
> CREATE SEQUENCE myseq001 INCREMENT 5 START 100;
> SELECT * from pg_sequences; -->shows last_val as NULL
>
> on SUB:
> CREATE SEQUENCE myseq001 INCREMENT 5 START 100;
> SELECT * from pg_sequences; -->correctly shows last_val as NULL
> ALTER SUBSCRIPTION sub1 REFRESH PUBLICATION SEQUENCES;
> SELECT * from pg_sequences; -->wrongly updates last_val to 100; it is
> still NULL on Pub.
>
> Thus , SELECT nextval('myseq001') on pub gives 100, while on sub gives 105.
> -----------
>
>
> [2]:
> -----------
> Pub:
> CREATE SEQUENCE myseq0 INCREMENT 5 START 10;
> SELECT * from pg_sequences;
>
> Sub:
> CREATE SEQUENCE myseq0 INCREMENT 5 MINVALUE 100;
>
> Pub:
> SELECT nextval('myseq0');
> SELECT nextval('myseq0');
>
> Sub:
> ALTER SUBSCRIPTION sub1 REFRESH PUBLICATION SEQUENCES;
> --check 'last_value', it is 15 while min_value is 100
> SELECT * from pg_sequences;

Thanks for reporting this, these issues are fixed in the attached
v20240730_2 version patch.

Regards,
Vignesh