Re: strange explain
От | Zeugswetter Andreas SB SD |
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Тема | Re: strange explain |
Дата | |
Msg-id | 46C15C39FEB2C44BA555E356FBCD6FA4961DCA@m0114.s-mxs.net обсуждение исходный текст |
Ответ на | strange explain (Oleg Bartunov <oleg@sai.msu.su>) |
Ответы |
Re: strange explain
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Список | pgsql-hackers |
> EXPLAIN > tour=# explain analyze select * from tours where > ( operator_id in (2,3,4,5,7) and type_id = 4 ) or > ( operator_id = 8 and type_id = 3); > NOTICE: QUERY PLAN: > > Index Scan using type_idx, type_idx, type_idx, type_idx, type_idx, type_idx on tours (cost=> > 0.00..12.25 rows=1 width=1091) (actual time=0.27..0.27 rows=0 loops=1) > Total runtime: 0.44 msec Actually this plan looks very strange to me. One would expect it to only use type_idx twice (in lack of a better index (type_id, operator_id)). Fetch all rows with type_id=4 and then filter the result on operator_id in (...), then do type_id=3 and filter operator_id=8. Seems there is room for another performance improvement here :-) Andreas
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