From: Mihail Nasedkin <m.nasedkin.perm@mail.ru>
To: pgsql-sql@postgresql.org
Subject: Re: index scan
Date: Mon, 21 Mar 2005 15:05:15 +0500
Message-ID: <12925969953.20050321150515@mail.ru> (raw)
In-Reply-To: <423E90BC.80501@archonet.com>
References: <10520036015.20050321132621@mail.ru>
<423E90BC.80501@archonet.com>
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: m.nasedkin.perm@mail.ru
Subject: Re: index scan
In-Reply-To: <12925969953.20050321150515@mail.ru>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox