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From: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Date: Wed, 30 Aug 2023 19:11:59 +0530
Message-ID: <CAExHW5vv-78ixJs3arsuZ+12A4AyqehJnDPhejp0m4FAKG6JZA@mail.gmail.com>
Subject: Re: [17] CREATE SUBSCRIPTION ... SERVER
To: Jeff Davis <pgsql@j-davis.com>
Cc: pgsql-hackers@postgresql.org
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Hi Jeff,

On Wed, Aug 30, 2023 at 2:12=E2=80=AFPM Jeff Davis <pgsql@j-davis.com> wrot=
e:
>
> The server "myserver" must have been created with the new syntax:
>
>    CREATE SERVER myserver FOR CONNECTION ONLY
>
> instead of specifying FOREIGN DATA WRAPPER. In other words, a server
> FOR CONNECTION ONLY doesn't have a real FDW, it's a special server just
> used for the postgres connection options. To create a server FOR
> CONNECTION ONLY, the user must be a member of the new predefined role
> pg_create_connection. A server FOR CONNECTION ONLY still uses ACLs and
> user mappings the same way as other foreign servers, but cannot be used
> to create foreign tables.

Are you suggesting that SERVERs created with FDW can not be used as
publishers? I think there's value in knowing that the publisher which
contains a replica of a table is the same as the foreign server which
is referenced by another foreign table. We can push down a join
between a replicated table and foreign table down to the foreign
server. A basic need for sharding with replicated tables. Of course
there's a lot work that we have to do in order to actually achieve
such a push down but by restricting this feature to only CONNECTION
ONLY, we are restricting the possibility of such a push down.

--=20
Best Wishes,
Ashutosh Bapat