| From: | Etsuro Fujita <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp> |
|---|---|
| To: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Odd plan shown in src/backend/optimizer/README |
| Date: | 2017-01-23 10:11:46 |
| Message-ID: | e6cfbaa3-af02-1abc-c25e-8fa5c6bc4e21@lab.ntt.co.jp |
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| Lists: | pgsql-hackers |
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
| Attachment | Content-Type | Size |
|---|---|---|
| optimizer-readme.patch | text/x-patch | 913 bytes |
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