[pgpool-general: 1534] Re: foreign data wrappers support?

Tatsuo Ishii ishii at postgresql.org
Thu Mar 28 08:31:24 JST 2013

>>> I'm mostly thinking & planning for 9.3 when a postgres FDW will be
>>> supported ( http://www.postgresql.org/docs/devel/static/postgres-fdw.html
>>> ).  This opens up a lot of new & interesting possibilities, especially
>>> with respect to clustering & load balancing, as it will be (somewhat)
>>> trivially possible to access different clusters from each other.
>> Can you elaborate on clustering & load balancing by using pgsql_fdw
>> with pgpool-II?
>> --
> What I was envisioning (granted this is all theoretical, I haven't
> tried to do any of it yet) was using pgsql_fdw to link two completely
> separate postgres clusters, both of which would have their own pgpool
> instances.  The 'CREATE SERVER' command would reference the port
> number of the second pgpool instance, rather than the postgres server
> itself.  As a result, any of the tables associated with the foreign
> postgres server would actually have their SQL queries going directly
> over the second pgpool instance.  I'm wondering if this should work as
> far as pgpool is concerned?

I think the configuration should work as expected because pgpool-II is
transparent to PostgreSQL protocol and I believe pgsql_fdw does not
invent any new PostgreSQL protocol attributes.

BTW, is there any concrete use case for such a configuration in your
mind? The configuration sounds pretty interesting but I cannot think
of real world use case.
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

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