Re: index scan
От | Mihail Nasedkin |
---|---|
Тема | Re: index scan |
Дата | |
Msg-id | 12925969953.20050321150515@mail.ru обсуждение исходный текст |
Ответ на | Re: index scan (Richard Huxton <dev@archonet.com>) |
Список | pgsql-sql |
Die, Richard. Thank you for answer March, 21 2005 14:15:40: RH> Mihail Nasedkin wrote: >> xxxx=# explain select * from sites s join site_screens ss on >> s.oid = ss.id_site; QUERY PLAN >> --------------------------------------------------------------------------- >> Hash Join (cost=...) >> Hash Cond: ("outer".id_site = "inner".oid) >> -> Seq Scan on site_screens ss (cost=...) >> -> Hash (cost=...) >> -> Seq Scan on sites s (cost=...) RH> You've commented out the interesting bits (the costs/rows) In that example main point - Seq Scan on site_screens >> I want to Index Scan. What must I do? RH> Why do you want an index scan? Do you have any evidence it will be RH> faster than a sequential scan? No, but I want to be ready for make Index scan queries in future. I make first steps on the customize SQL. Where I can read more about optimize the SQL-queries and about differences between types of scan? -- Regards,Mihail Nasedkinm.nasedkin.perm@mail.ru
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