Re: Added schema level support for publication.

On Mon, Jul 19, 2021 at 9:32 AM tanghy(dot)fnst(at)fujitsu(dot)com <
tanghy(dot)fnst(at)fujitsu(dot)com> wrote:
>
> On Friday, July 16, 2021 6:10 PM vignesh C <vignesh21(at)gmail(dot)com>
> > On Wed, Jul 14, 2021 at 6:25 PM houzj(dot)fnst(at)fujitsu(dot)com
> > <houzj(dot)fnst(at)fujitsu(dot)com> wrote:
> > >
> > > Wednesday, July 14, 2021 6:17 PM vignesh C <vignesh21(at)gmail(dot)com>
wrote:
> > > > On Tue, Jul 13, 2021 at 12:06 PM tanghy(dot)fnst(at)fujitsu(dot)com
> > > > <tanghy(dot)fnst(at)fujitsu(dot)com> wrote:
> > > > >
> > > > > On Monday, July 12, 2021 5:36 PM vignesh C <vignesh21(at)gmail(dot)com>
> > wrote:
> > > > > >
> > > > > > Thanks for reporting this issue, this issue is fixed in the v10
> > > > > > patch attached at [1].
> > > > > > [1] - https://www.postgresql.org/message-id/CALDaNm2%2BtR%2B8R-
> > > > > > sD1CSyMbZcZbkintZE-avefjsp7LCkm6HMmw%40mail.gmail.com
> > > > >
> > > > > Thanks for fixing it.
> > > > >
> > > > > By applying your V10 patch, I saw three problems, please have a
look.
> > > > >
> > > > > 1. An issue about pg_dump.
> > > > > When public schema was published, the publication was created in
the
> > > > > output file, but public schema was not added to it. (Other schemas
> > > > > could be added as expected.)
> > > > >
> > > > > I looked into it and found that selectDumpableNamespace function
marks
> > > > DUMP_COMPONENT_DEFINITION as needless when the schema is public,
> > > > leading to schema public is ignored in getPublicationSchemas. So
we'd better
> > > > check whether schemas should be dumped in another way.
> > > > >
> > > > > I tried to fix it with the following change, please have a look.
> > > > > (Maybe we also need to add some comments for it.)
> > > > >
> > > > > diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
> > > > > index f6b4f12648..a327d2568b 100644
> > > > > --- a/src/bin/pg_dump/pg_dump.c
> > > > > +++ b/src/bin/pg_dump/pg_dump.c
> > > > > @@ -4206,7 +4206,8 @@ getPublicationSchemas(Archive *fout,
> > > > NamespaceInfo nspinfo[], int numSchemas)
> > > > > * Ignore publication membership of schemas whose
> > > > definitions are not
> > > > > * to be dumped.
> > > > > */
> > > > > - if (!(nsinfo->dobj.dump &
> > > > DUMP_COMPONENT_DEFINITION))
> > > > > + if (!((nsinfo->dobj.dump &
> > > > DUMP_COMPONENT_DEFINITION)
> > > > > + || (strcmp(nsinfo->dobj.name, "public")
== 0
> > > > > + && nsinfo->dobj.dump != DUMP_COMPONENT_NONE)))
> > > > > continue;
> > > > >
> > > > > pg_log_info("reading publication membership for
schema
> > > > > \"%s\"",
> > > >
> > > > I felt it is intentionally done like that as the pubic schema is
created by default,
> > > > hence it is not required to dump else we will get errors while
restoring.
> > > > Thougths?
> > >
> > > Thanks for the new patches and I also looked at this issue.
> > >
> > > For user defined schema and publication:
> > > --------------------------
> > > create schema s1;
> > > create publication pub2 for SCHEMA s1;
> > > --------------------------
> > >
> > > pg_dump will only generate the following SQLs:
> > >
> > > ------pg_dump result------
> > > CREATE PUBLICATION pub2 WITH (publish = 'insert, update, delete,
truncate');
> > > ALTER PUBLICATION pub2 ADD SCHEMA s1;
> > > --------------------------
> > >
> > > But for the public schema:
> > > --------------------------
> > > create publication pub for SCHEMA public;
> > > --------------------------
> > >
> > > pg_dump will only generate the following SQL:
> > >
> > > ------pg_dump result------
> > > CREATE PUBLICATION pub WITH (publish = 'insert, update, delete,
truncate');
> > > --------------------------
> > >
> > > It didn't generate SQL like "ALTER PUBLICATION pub ADD SCHEMA
public;" which
> > > means the public schema won't be published after restoring. So, I
think we'd
> > > better let the pg_dump generate the ADD SCHEMA public SQL. Thoughts ?
> >
> > Thanks for reporting this issue, this issue is fixed in the v12 patch
attached.
> >
>
> I tested your v12 patch and found a problem in the following case.
>
> Step 1:
> postgres=# create schema s1;
> CREATE SCHEMA
> postgres=# create table s1.t1 (a int);
> CREATE TABLE
> postgres=# create publication pub_t for table s1.t1;
> CREATE PUBLICATION
> postgres=# create publication pub_s for schema s1;
> CREATE PUBLICATION
>
> Step 2:
> pg_dump -N s1
>
> I dumped and excluded schema s1, pg_dump generated the following SQL:
> -------------------------------
> ALTER PUBLICATION pub_s ADD SCHEMA s1;
>
> I think it was not expected because SQL like "ALTER PUBLICATION pub_t ADD
TABLE s1.t1" was not generated in my case. Thoughts?

Thanks for reporting this issue, this issue is fixed in the v13 patch
posted at [1]
[1] -
https://www.postgresql.org/message-id/CALDaNm0%3DMaXyAok5iq_-DeWUd81vpdF47-MZbbrsd%2BzB2P6WwA%40mail.gmail.com

Regards,
Vignesh