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Re: two queries and dual cpu (perplexed)

From: Jeff <threshar(at)torgo(dot)978(dot)org>
To: "Shoaib Burq (VPAC)" <sab(at)vpac(dot)org>
Cc: performance pgsql <pgsql-performance(at)postgresql(dot)org>
Subject: Re: two queries and dual cpu (perplexed)
Date: 2005-04-22 11:48:29
Message-ID: ec08c6c467efe0132625ea1a80a20561@torgo.978.org (view raw or flat)
Thread:
Lists: 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(at)jefftrout(dot)com>
http://www.jefftrout.com/
http://www.stuarthamm.net/


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