Re: Logical Replication of sequences

On Thu, 25 Jul 2024 at 15:41, shveta malik <shveta(dot)malik(at)gmail(dot)com> wrote:
>
> On Thu, Jul 25, 2024 at 12:08 PM 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]
>
> One more issue:
> 3) Sequence datatype's range is not honored on sub during
> replication, while it is honored for tables.
>
>
> Behaviour for tables:
> ---------------------
> Pub: create table tab1( i integer);
> Sub: create table tab1( i smallint);
>
> Pub: insert into tab1 values(generate_series(1, 32768));
>
> Error on sub:
> 2024-07-25 10:38:06.446 IST [178680] ERROR: value "32768" is out of
> range for type smallint
>
> ---------------------
> Behaviour for sequences:
> ---------------------
>
> Pub:
> CREATE SEQUENCE myseq_i as integer INCREMENT 10000 START 1;
>
> Sub:
> CREATE SEQUENCE myseq_i as smallint INCREMENT 10000 START 1;
>
> Pub:
> SELECT nextval('myseq_i');
> SELECT nextval('myseq_i');
> SELECT nextval('myseq_i');
> SELECT nextval('myseq_i');
> SELECT nextval('myseq_i'); -->brings value to 40001
>
> Sub:
> ALTER SUBSCRIPTION sub1 REFRESH PUBLICATION SEQUENCES;
> SELECT * from pg_sequences; -->last_val reached till 40001, while the
> range is till 32767.

This issue is addressed in the v20240730_2 version patch attached at [1].
[1] - https://www.postgresql.org/message-id/CALDaNm3%2BXzHAbgyn8gmbBLK5goyv_uyGgHEsTQxRZ8bVk6nAEg%40mail.gmail.com

Regards,
Vignesh