On 2015/09/29 9:13, Kouhei Kaigai wrote:
-----Original Message-----
From: pgsql-hackers-ow...@postgresql.org
[mailto:pgsql-hackers-ow...@postgresql.org] On Behalf Of Robert Haas
Sent: Tuesday, September 29, 2015 5:46 AM
To: Kaigai Kouhei(海外 浩平)
Cc: Etsuro Fujita; PostgreSQL-development; 花田茂
Subject: Re: [HACKERS] Foreign join pushdown vs EvalPlanQual
On Mon, Sep 28, 2015 at 3:34 AM, Kouhei Kaigai <kai...@ak.jp.nec.com> wrote:
The attached patch allows FDW driver to handle EPQ recheck by its own
preferable way, even if it is alternative local join or ExecQual to
the expression being pushed down.
Thanks for the work, KaiGai-san!
Thanks. I was all set to commit this, or at least part of it, when I
noticed that we already have an FDW callback called RefetchForeignRow.
We seem to be intending that this new callback should refetch the row
from the foreign server and verify that any pushed-down quals apply to
it. But why can't RefetchForeignRow do that? That seems to be what
it's for.
Thanks for the comments, Robert!
I thought the same thing [1]. While I thought it was relatively easy to
make changes to RefetchForeignRow that way for the foreign table case
(scanrelid>0), I was not sure how hard it would be to do so for the
foreign join case (scanrelid==0). So, I proposed to leave that changes
for 9.6. I'll have a rethink on this issue along the lines of that
approach.
Sorry for having had no response. I was on vacation.
Best regards,
Etsuro Fujita
[1] http://www.postgresql.org/message-id/55deb5a9.8010...@lab.ntt.co.jp
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