Re: pgsql_fdw, FDW for PostgreSQL server

(2011/10/25 19:15), Magnus Hagander wrote:
> 2011/10/25 Shigeru Hanada<shigeru(dot)hanada(at)gmail(dot)com>:
>> I'd like to propose pgsql_fdw, FDW for external PostgreSQL server, as a
>> contrib module. I think that this module would be the basis of further
>> SQL/MED development for core, e.g. join-push-down and ANALYZE support.
>
> I have not looked at the code itself, but I wonder if we shouldn't
> consider making this a part of core-proper, not just a contrib module.
> The fact that it isn't *already* available in core surprises a lot of
> people...

Do you mean that pgsql_fdw should be a built-in extension like plpgsql
so that it's available just after initdb? It would be accomplished with
some more changes:

* Move pgsql_fdw into core, say src/backend/foreign/libpgsql_fdw, and
install dynamically loadable module during "make install" for core. The
pgsql_fdw_handler function can't be included into core binary because we
must avoid liking libpq with server binary directly. This method is
also used for libwalreceiver of replication module.
* Create pgsql_fdw extension during initdb invocation, like plpgsql.

These are not trivial, but not difficult so much. However, I think
contrib would be the appropriate place for pgsql_fdw because it's
(relatively) special feature.
--
Shigeru Hanada