Re: Added schema level support for publication.

On Sun, Aug 15, 2021 at 12:23 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Peter Eisentraut <peter.eisentraut@enterprisedb.com> writes:
> > I think the strict separation between publication-for-tables vs.
> > publication-for-schemas is a mistake.  Why can't I have a publication
> > that publishes tables t1, t2, t3, *and* schemas s1, s2, s3.  Also note
> > that we have a pending patch to add sequences support to logical
> > replication.  So eventually, a publication will be able to contain a
> > bunch of different objects of different kinds.
>
> This seems like it's going to create a mess, because the meaning of
> "include schema S" will change over time as we add more features.
> That is, with the present patch (I suppose, haven't read it) we have
> "schema S" meaning "publish all tables in schema S".  When that other
> patch lands, presumably that same publication definition would start
> meaning "publish all tables and sequences in schema S".  And a few years
> down the road it might start meaning something else again.  That sounds
> like the sort of potentially app-breaking change that we don't like
> to make.
>
> We could avoid that bug-in-waiting if the syntax were more like
> "FOR ALL TABLES IN SCHEMA s", which could later extend to
> "FOR ALL SEQUENCES IN SCHEMA s", etc.  This is then a very clean
> intermediate step between publishing one table and "FOR ALL TABLES"
> without a schema limitation.

+1

> I tend to agree that a single publication should be able to incorporate
> any of these options.

I personally prefer that a single publication can include both all
tables and all sequences in a database or a schema. It would be a more
convenient way to specify replicating all objects (tables and
sequences) in a database or a schema.

Regards,

-- 
Masahiko Sawada
EDB:  https://www.enterprisedb.com/