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Re: Why is the query not using the index for sorting?

From: Jonathan Blitz <jblitz(at)013(dot)net>
To: 'Matthew Wakeling' <matthew(at)flymine(dot)org>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Why is the query not using the index for sorting?
Date: 2009-11-23 14:10:57
Message-ID: 29E33C74F48D41AC93995E684525D58F@jblaptop (view raw or flat)
Thread:
Lists: pgsql-performance
Definitely after.

Jonathan 

-----Original Message-----
From: pgsql-performance-owner(at)postgresql(dot)org
[mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of Matthew
Wakeling
Sent: Monday, November 23, 2009 1:00 PM
To: Jonathan Blitz
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] Why is the query not using the index for sorting?

On Sun, 22 Nov 2009, Jonathan Blitz wrote:
> I have a table with a number of columns.
>  
> I perform
>  
> Select *
> from table
> order by a,b
>  
> There is an index on a,b which is clustered (as well as indexes on a and b
alone).
> I have issued the cluster and anyalze commands.

Did you analyse *after* creating the index and clustering, or before?

Matthew

--
 [About NP-completeness] These are the problems that make efficient use of
 the Fairy Godmother.                    -- Computer Science Lecturer
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Subject: Re: View based upon function won't use index on joins
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Subject: Re: Query times change by orders of magnitude as DB ages

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