From: | Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com> |
---|---|
To: | Shigeru Hanada <shigeru(dot)hanada(at)gmail(dot)com> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Writable foreign tables: how to identify rows |
Date: | 2013-03-06 11:15:58 |
Message-ID: | C00CA10F-E214-4FC5-ACC9-E3F6732AB17A@gmail.com |
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On 06-Mar-2013, at 4:12 PM, Shigeru Hanada <shigeru(dot)hanada(at)gmail(dot)com> wrote:
> On Wed, Mar 6, 2013 at 12:35 PM, Pavan Deolasee
> <pavan(dot)deolasee(at)gmail(dot)com> wrote:
>> In the context of postgres_fdw, I am not sure if we need an additional
>> system column like a node_id. Would there be a possibility where
>> tuples to-be-modified are coming from different foreign tables and at
>> runtime we need to decide where to execute the UPDATE/DELETE operation
>> ? If we start supporting inheritance involving foreign tables as child
>> tables, this will become a reality.
>
> Foreign tables have tableoid system column which holds pg_class.oid of
> the foreign table. It seems sufficient to determine source server.
>
I think you are right. In the context of foreign tables, tableoid might be enough to get the source. Unfortunately, Postgres-XC had not yet leveraged foreign tables fully and hence special handling was required.
Thanks,
Pavan
> --
> Shigeru HANADA
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