Date: Mon, 21 Mar 2005 15:05:15 +0500
From: Mihail Nasedkin <m.nasedkin.perm@mail.ru>
Reply-To: Mihail Nasedkin <m.nasedkin.perm@mail.ru>
Message-ID: <12925969953.20050321150515@mail.ru>
To: pgsql-sql@postgresql.org
Subject: Re: index scan
In-Reply-To: <423E90BC.80501@archonet.com>
References: <10520036015.20050321132621@mail.ru> <423E90BC.80501@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 Nasedkin
 m.nasedkin.perm@mail.ru