Re: Foreign join pushdown vs EvalPlanQual

On 2015/11/13 11:31, Kouhei Kaigai wrote:
>>>> On 2015/11/12 2:53, Robert Haas wrote:
>>>>> From my point of view I'm now
>>>>> thinking this solution has two parts:
>>>>>
>>>>> (1) Let foreign scans have inner and outer subplans. For this
>>>>> purpose, we only need one, but it's no more work to enable both, so we
>>>>> may as well. If we had some reason, we could add a list of subplans
>>>>> of arbitrary length, but there doesn't seem to be an urgent need for
>>>>> that.

I wrote:
>> But one thing I'm concerned about is enable both inner and
>> outer plans, because I think that that would make the planner
>> postprocessing complicated, depending on what the foreign scans do by
>> the inner/outer subplans. Is it worth doing so? Maybe I'm missing
>> something, though.

> If you persuade other person who has different opinion, you need to
> explain why was it complicated, how much complicated and what was
> the solution you tried at that time.
> The "complicated" is a subjectively-based term. At least, we don't
> share your experience, so it is hard to understand the how complexity.

I don't mean to object that idea. I'm unfamiliar with that idea, so I
just wanted to know the reason, or use cases.

Best regards,
Etsuro Fujita