Re: Can this query be optimized?
От | Josh Berkus |
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Тема | Re: Can this query be optimized? |
Дата | |
Msg-id | web-501647@davinci.ethosmedia.com обсуждение исходный текст |
Ответ на | Re: Can this query be optimized? (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Can this query be optimized?
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Список | pgsql-sql |
Claus, > > I'm stuck optimizing the following query: > > select distinct extract(year from date) as year, extract(month from > date) > > as month, date from week_pics order by date desc; > > Perhaps it would work to forget the "distinct" and instead GROUP BY > date. Also, do the following: -- Make sure you have an index on week_pics.date (Tom, did you guys ever straignten out the issue with DESC sorts on indexes?) -- Build the above query as a VIEW, which should improve performance somewhat. Technically, you could build an index on extract(month from date), I believe, but I'm not sure how effective such an index would be in practice. -Josh ______AGLIO DATABASE SOLUTIONS___________________________ Josh Berkus Complete informationtechnology josh@agliodbs.com and data management solutions (415) 565-7293 for law firms, small businesses fax 621-2533 and non-profit organizations. San Francisco
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