Re: index scan

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От Mihail Nasedkin
Тема Re: index scan
Дата
Msg-id 12925969953.20050321150515@mail.ru
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Ответ на Re: index scan  (Richard Huxton <dev@archonet.com>)
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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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