Re: Odd system-column handling in postgres_fdw join pushdown patch - Mailing list pgsql-hackers

From Etsuro Fujita
Subject Re: Odd system-column handling in postgres_fdw join pushdown patch
Date
Msg-id 570F0CCB.50008@lab.ntt.co.jp
Whole thread Raw
In response to Re: Odd system-column handling in postgres_fdw join pushdown patch  (Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>)
Responses Re: Odd system-column handling in postgres_fdw join pushdown patch  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On 2016/04/14 12:04, Etsuro Fujita wrote:
> On 2016/04/14 4:57, Robert Haas wrote:
>> 2. When a join is pushed down, deparse system columns using something
>> like "CASE WHEN r1.* IS NOT NULL THEN 0 END", except for the table OID
>> column, which gets deparsed with the table OID in place of 0.  This
>> delivers the correct behavior in the presence of outer joins.

> I think that that would cause useless data transfer for such culumns.
> Why not set values locally for such columns?

At least for the table OID.

Best regards,
Etsuro Fujita





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