Обсуждение: [HACKERS] Odd plan shown in src/backend/optimizer/README

While working on a bug in postgres_fdw, I found this:

      NestLoop
          -> Seq Scan on SmallTable1 A
          NestLoop
              -> Seq Scan on SmallTable2 B
              NestLoop
                  -> Index Scan using XYIndex on LargeTable C
                        Index Condition: C.X = A.AID and C.Y = B.BID

This seems odd to me; we would not need the bottom-level Nestloop.  
Attached is a small patch for fixing that.  I also adjusted the  
indentation to the last line "Index Condition: ...", to match others in  
the section of Parameterized Paths.

Best regards,
Etsuro Fujita

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Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp> writes:
> This seems odd to me; we would not need the bottom-level Nestloop.  
> Attached is a small patch for fixing that.

Pushed, thanks.
        regards, tom lane

On 2017/01/23 23:39, Tom Lane wrote:
> Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp> writes:
>> This seems odd to me; we would not need the bottom-level Nestloop.
>> Attached is a small patch for fixing that.

> Pushed, thanks.

Thank you for picking this up!

Best regards,
Etsuro Fujita