Re: Add an option to skip loading missing publication to avoid logical replication failure

On Mon, 10 Mar 2025 at 09:33, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Tue, Mar 4, 2025 at 6:54 PM vignesh C <vignesh21(at)gmail(dot)com> wrote:
> >
> > On further thinking, I felt the use of publications_updated variable
> > is not required we can use publications_valid itself which will be set
> > if the publication system table is invalidated. Here is a patch for
> > the same.
> >
>
> The patch relies on the fact that whenever a publication's data is
> invalidated, it will also invalidate all the RelSyncEntires as per
> publication_invalidation_cb. But note that we are discussing removing
> that inefficiency in the thread [1]. So, we should try to rebuild the
> entry when we have skipped the required publication previously.
>
> Apart from this, please consider updating the docs, as mentioned in my
> response to Sawada-San's email.

The create subscription documentation already has "We allow
non-existent publications to be specified so that users can add those
later. This means pg_subscription can have non-existent publications."
and should be enough at [1]. Let me know if we need to add more
documentation.

Apart from this I have changed the log level that logs "skipped
loading publication" to WARNING as we log a warning "WARNING:
publications "pub2", "pub3" do not exist on the publisher" in case of
CREATE SUBSCRIPTION and looked similar to this. I can change it to a
different log level in case you feel this is not the right level.

Also I have added a test case for dilip's comment from [2].
The attached v7 version patch has the changes for the same.

[1] - https://www.postgresql.org/docs/devel/sql-createsubscription.html
[2] - https://www.postgresql.org/message-id/CAFiTN-tgUR6QLSs3UHK7gx4VP7cURGNkufA_xkrQLw9eCnbGQw%40mail.gmail.com

Regards,
Vignesh