Re: Foreign join pushdown vs EvalPlanQual - Mailing list pgsql-hackers

From Kouhei Kaigai
Subject Re: Foreign join pushdown vs EvalPlanQual
Date
Msg-id 9A28C8860F777E439AA12E8AEA7694F80117298C@BPXM15GP.gisp.nec.co.jp
Whole thread Raw
In response to Re: Foreign join pushdown vs EvalPlanQual  (Kouhei Kaigai <kaigai@ak.jp.nec.com>)
Responses Re: Foreign join pushdown vs EvalPlanQual  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
> > On Sun, Nov 8, 2015 at 7:26 PM, Kouhei Kaigai <kaigai@ak.jp.nec.com> wrote:
> > > The attached patch is an adjusted version of the previous one.
> > > Even though it co-exists a new callback and fdw_recheck_quals,
> > > the callback is kicked first as follows.
> >
> > This seems excessive to me: why would we need an arbitrary-length list
> > of plans for an FDW?  I think we should just allow an outer child and
> > an inner child, which is probably one more than we'll ever need in
> > practice.
> >
> It just intends to keep code symmetry with custom-scan case, so not
> a significant reason.
> And, I expected ForeignScan will also need multiple sub-plans soon
> to support more intelligent push-down like:
> http://www.postgresql.org/message-id/9A28C8860F777E439AA12E8AEA7694F8010F47D
> A@BPXM15GP.gisp.nec.co.jp
> 
> It is a separate discussion, of course, so I don't have strong preference
> here.
> 
> > This looks like an independent bug fix:
> >
> > +               fscan->fdw_recheck_quals = (List *)
> > +                       fix_upper_expr(root,
> > +                                                  (Node *)
> > fscan->fdw_recheck_quals,
> > +                                                  itlist,
> > +                                                  INDEX_VAR,
> > +                                                  rtoffset);
> >                 pfree(itlist);
> >
> > If so, it should be committed separately and back-patched to 9.5.
> >
> OK, I'll split the patch into two.
>
The attached patch is the portion cut from the previous EPQ recheck
patch.

Regarding of the fdw_plans or fdw_plan, I'll follow your suggestion.

Thanks,
--
NEC Business Creation Division / PG-Strom Project
KaiGai Kohei <kaigai@ak.jp.nec.com>


Attachment

pgsql-hackers by date:

Previous
From: Masahiko Sawada
Date:
Subject: Re: Freeze avoidance of very large table.
Next
From: Etsuro Fujita
Date:
Subject: Re: Minor comment improvement to create_foreignscan_plan