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

On Tue, Mar 11, 2025 at 4:01 PM vignesh C <vignesh21(at)gmail(dot)com> wrote:
>
> 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.
>

Thanks, Vignesh, for adding the test. I believe you've tested the
effect of DROP PUBLICATION. However, I think we should also test the
behavior of ALTER SUBSCRIPTION...SET PUBLICATION before creating the
PUBLICATION, and then create the PUBLICATION at a later stage.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com