Re: Added schema level support for publication.

On Fri, Jan 22, 2021 at 10:01 AM vignesh C <vignesh21(at)gmail(dot)com> wrote:
>
> Thanks Rahila for your comments. Please find my thoughts below:
>
> On Wed, Jan 20, 2021 at 6:27 PM Rahila Syed <rahilasyed90(at)gmail(dot)com> wrote:
> >
> > Hi Vignesh,
> >
> >>
> >> I have handled the above scenario(drop schema should automatically
> >> remove the schema entry from publication schema relation) & addition
> >> of tests in the new v2 patch attached.
> >> Thoughts?
> >
> >
> > Please see some initial comments:
> >
> > 1. I think there should be more tests to show that the schema data is actually replicated
> > to the subscriber. Currently, I am not seeing the data being replicated when I use FOR SCHEMA.
> >
> I will fix this issue and include more tests in my next version of the patch.

Modified to handle this and also added a few more tests.

> > 2. How does replication behave when a table is added or removed from a subscribed schema
> > using ALTER TABLE SET SCHEMA?
> >
> I would like to keep the behavior similar to the table behavior. I
> will post more details for this along with my next version of the
> patch.
>

If a table is set to a different schema, after the schema change table
data will not be sent to the subscriber.
When a new table is added to the published schema, the table data will
be sent by the publisher, subscriber will not apply the changes. If
the change needs to be reflected, subscriber's publication should be
refreshed using "alter subscription mysub1 refresh publication". This
relation will be reflected in the subscriber relation when the
subscriber's publication is refreshed.
If a table is dropped, there is no impact on subscriber, This relation
will be present in pg_subscriber_rel after refreshing subscriber
publication.

> > 3. Can we have a default schema like a public or current schema that gets replicated in case the user didn't
> > specify one, this can be handy to replicate current schema tables.
> >
> It looks like a good use case, I will check on the feasibility of this
> and try to implement this.

This can be done, I will handle this later.

> > 4. + The fourth, fifth and sixth variants change which schemas are part of the
> > + publication. The <literal>SET TABLE</literal> clause will replace the list
> > + of schemas in the publication with the specified one. The <literal>ADD
> >
> > There is a typo above s/SET TABLE/SET SCHEMA
> I will fix this in the next version of the patch.

Modified it.
I have separated the tests and documentation into a separate patch to
make review easier. Attached v3 patch with the fixes.
Thoughts?

Regards,
Vignesh