Re: two queries and dual cpu (perplexed)
От | Jeff |
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Тема | Re: two queries and dual cpu (perplexed) |
Дата | |
Msg-id | ec08c6c467efe0132625ea1a80a20561@torgo.978.org обсуждение исходный текст |
Ответ на | Re: two queries and dual cpu (perplexed) ("Shoaib Burq (VPAC)" <sab@vpac.org>) |
Список | pgsql-performance |
On Apr 21, 2005, at 11:33 PM, Shoaib Burq (VPAC) wrote: > > BTW I guess should mention that I am doing the select count(*) on a > View. > A bit of a silly question... but are you actually selecting all the rows from this query in production or would it be more selective? ie select * from bigslowview where bah = 'snort'? > Ran the Explain analyse with the nestedloop disabled but it was taking > forever... and killed it after 30mins. > If it takes too long you can run just plain explain (no analyze) and it will show you the plan. This is nearly always instant... it'll give you a clue as to if your setting changes did anything. You may need to end up breaking some parts of this up into subqueries. I've had to do this before. I had one query that just ran too dang slow as a join so I modified it into a subquery type deal. Worked great. However since you are selecting ALL rows I doubt that will help much. Another option may be to use materialized views. Not sure how "dynamic" your data model is. It could help. -- Jeff Trout <jeff@jefftrout.com> http://www.jefftrout.com/ http://www.stuarthamm.net/
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