On Fri, May 7, 2021 at 7:35 PM Andrey Lepikhov
<a.lepikhov@postgrespro.ru> wrote:
> On 6/5/21 14:11, Etsuro Fujita wrote:
> > On Tue, Apr 27, 2021 at 3:57 PM Andrey V. Lepikhov
> > <a.lepikhov@postgrespro.ru> wrote:
> >> One more question. Append choose async plans at the stage of the Append
> >> plan creation.
> >> Later, the planner performs some optimizations, such as eliminating
> >> trivial Subquery nodes. So, AsyncAppend is impossible in some
> >> situations, for example:
> >>
> >> (SELECT * FROM f1 WHERE a < 10)
> >> UNION ALL
> >> (SELECT * FROM f2 WHERE a < 10);
> >> We can choose async
> >> subplans at the beginning of the execution stage.
> >> For a demo, I prepared the patch (see in attachment).
> >> It solves the problem and passes the regression tests.
> >
> > IIUC, another approach to this would be the
> > patch you proposed before [1]. Right?
> Yes. I think, new solution will be better.
Ok, will review.
I think it would be better to start a new thread for this, and add the
patch to the next CF so that it doesn’t get lost.
Best regards,
Etsuro Fujita
