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From: vignesh C <vignesh21@gmail.com>
Date: Tue, 10 May 2022 09:08:48 +0530
Message-ID: 
 <CALDaNm18VH2j8cTqfELHQ=0ZNognbGBhbHPteJenWQC6C2dueQ@mail.gmail.com>
Subject: Re: Skipping schema changes in publication
To: Peter Smith <smithpb2250@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>,
	Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Fri, May 6, 2022 at 8:05 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> On Thu, Apr 28, 2022 at 9:32 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> ...
> >
> > Another idea that occurred to me today for tables this is as follows:
> > 1. Allow to mention except during create publication ... For All Tables.
> > CREATE PUBLICATION pub1 FOR ALL TABLES EXCEPT TABLE t1,t2;
> > 2. Allow to Reset it. This new syntax will reset all objects in the
> > publications.
> > Alter Publication ... RESET;
> > 3. Allow to add it to an existing publication
> > Alter Publication ... Add ALL TABLES [EXCEPT TABLE t1,t2];
> >
> > I think it can be extended in a similar way for schema syntax as well.
> >
>
> If the proposed syntax ALTER PUBLICATION ... RESET will reset all the
> objects in the publication then there still seems simple way to remove
> only the EXCEPT list but leave everything else intact. IIUC to clear
> just the EXCEPT list would require a 2 step process - 1) ALTER ...
> RESET then 2) ALTER ... ADD ALL TABLES again.
>
> I was wondering if it might be useful to have a variation that *only*
> resets the EXCEPT list, but still leaves everything else as-is?
>
> So, instead of:
> ALTER PUBLICATION pubname RESET

+1 for this syntax as this syntax can be extendable to include options
like (except/all/etc) later.
Currently we can support this syntax and can be extended later based
on the requirements.

The new feature will handle the various use cases based on the
behavior given below:
-- CREATE Publication with EXCEPT TABLE syntax
CREATE PUBLICATION pub1 FOR ALL TABLES EXCEPT TABLE t1,t2; -- ok
Alter Publication pub1 RESET;
-- All Tables and options are reset similar to creating publication
without any publication object and publication option (create
publication pub1)
\dRp+ pub1
Publication pub2
Owner | All tables | Inserts | Updates | Deletes | Truncates | Via root
---------+------------+---------+---------+---------+-----------+----------
vignesh | f | t | t | t | t | f
(1 row)

-- Can add except table after reset of publication
ALTER PUBLICATION pub1 Add ALL TABLES EXCEPT TABLE t1,t2; -- ok

-- Cannot add except table without reset of publication
ALTER PUBLICATION pub1 Add EXCEPT TABLE t3,t4; -- not ok, need to be reset

Alter Publication pub1 RESET;
-- Cannot add table to ALL TABLES Publication
ALTER PUBLICATION pub1 Add ALL TABLES EXCEPT TABLE t1,t2, t3, t4,
TABLE t5; -- not ok, ALL TABLES Publications does not support
including of TABLES

Alter Publication pub1 RESET;
-- Cannot add table to ALL TABLES Publication
ALTER PUBLICATION pub1 Add ALL TABLES TABLE t1,t2; -- not ok, ALL
TABLES Publications does not support including of TABLES

-- Cannot add ALL TABLES IN SCHEMA to ALL TABLES Publication
ALTER PUBLICATION pub1 Add ALL TABLES ALL TABLES IN SCHEMA sch1, sch2;
-- not ok, ALL TABLES Publications does not support including of ALL
TABLES IN SCHEMA

-- Existing syntax should work as it is
CREATE PUBLICATION pub1 FOR TABLE t1;
ALTER PUBLICATION pub1 ADD TABLE t1; -- ok, existing ALTER should work
as it is (ok without reset)
ALTER PUBLICATION pub1 ADD ALL TABLES IN SCHEMA sch1; -- ok, existing
ALTER should work as it is (ok without reset)
ALTER PUBLICATION pub1 DROP TABLE t1; -- ok, existing ALTER should
work as it is (ok without reset)
ALTER PUBLICATION pub1 DROP ALL TABLES IN SCHEMA sch1; -- ok, existing
ALTER should work as it is (ok without reset)
ALTER PUBLICATION pub1 SET TABLE t1; -- ok, existing ALTER should work
as it is (ok without reset)
ALTER PUBLICATION pub1 SET ALL TABLES IN SCHEMA sch1; -- ok, existing
ALTER should work as it is (ok without reset)

I will modify the patch to handle this.

Regards,
Vignesh