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List:       postgresql-general
Subject:    Re: Antw: Re: [GENERAL] Query questions
From:       Richard Huxton <dev () archonet ! com>
Date:       2006-07-31 16:29:52
Message-ID: 44CE3000.9060501 () archonet ! com
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A. Kretschmer wrote:
> am  31.07.2006, um 15:55:39 +0100 mailte Richard Huxton folgendes:
>> Christian Rengstl wrote:
>>> My version is 8.1.4. Here is the plan for the query, it's performed on a
>>>                                    Total runtime: 1903.894 ms
>>> And yes i have indexes on both pid (varchar(15)) and crit(varchar(13)).
>> That's not quite what Andreas asked. Do you have an index on (pid, crit)?
> 
> He has 8.1, and i think, we have bitmap index scan for such tasks...
> (we don't need a index over both columns)

Hmm - I'd have assumed an index spanning both columns would be a win 
where the selectivity was reasonable (as it looked here). Reading 
through the original post, I'd be tempted to see if an index on 
(pid,crit,iDate) could be used for the sorting too. If the planner is 
smart enough to spot it, that would presumably be the best result.

-- 
   Richard Huxton
   Archonet Ltd

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