> On Thu, Nov 19, 2015 at 6:39 AM, Kouhei Kaigai <kaigai@ak.jp.nec.com> wrote:
> > So, are you suggesting to make a patch that allows ForeignScan to have
> > multiple sub-plans right now? Or, one sub-plan?
>
> Two:
>
> http://www.postgresql.org/message-id/CA+TgmoYZeje+ot1kX4wdoB7R7DPS0CWXAzfqZ-
> 14yKfkgKREAQ@mail.gmail.com
>
Hmm. Two is a bit mysterious for me because two sub-plans (likely)
means this ForeignScan node checks join clauses and reconstruct
a joined tuple by itself but does not check scan clauses pushed-
down (it is job of inner/outer scan plan, isn't it?).
In this case, how do we treat N-way remote join cases (N>2) if we
assume such a capability in FDW driver?
One subplan means FDW driver run an entire join sub-tree with local
alternative sub-plan; that is my expectation for the majority case.
However, I cannot explain two subplans, but not multiple, well.
Thanks,
--
NEC Business Creation Division / PG-Strom Project
KaiGai Kohei <kaigai@ak.jp.nec.com>
