need help optimizing query

From: rihad <rihad(at)mail(dot)ru>
To: pgsql-general(at)postgresql(dot)org
Subject: need help optimizing query
Date: 2008-02-02 10:50:31
Message-ID: 47A44AF7.2000003@mail.ru
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

Hi all,

The situation: there are users in one table, and their access statistics
in the other. Now I want to find users whose last access time was more
than one month ago. As I've only had to write quite simple queries
involving no sub-selects so far, I'd like to ask your opinion if this
one scales at all or not.

SELECT u.login,last_use_time
FROM users u
JOIN (SELECT user_id, MAX(stop_time) AS last_use_time
FROM stats
GROUP BY user_id) AS s ON (u.id=s.user_id)
WHERE status='3' AND next_plan_id IS NULL
AND last_use_time < now() - interval '1 month'
ORDER BY last_use_time;

It seems to do the job, but how good is it in the long run? Any way I
could tweak it?

Thanks.

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Olexandr Melnyk 2008-02-02 11:17:36 Re: need help optimizing query
Previous Message rihad 2008-02-02 09:10:45 help optimizing query