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From: PFC <[email protected]>
To: Steve Atkins <[email protected]>
To: PostgreSQL General <[email protected]>
Subject: Re: index vs. seq scan choice?
Date: Fri, 25 May 2007 10:09:17 +0200
Message-ID: <op.tsvh9ra1cigqcu@apollo13> (raw)
In-Reply-To: <[email protected]>
References: <8C5B026B51B6854CBE88121DBF097A86C3A30D@ehost010-33.exch010.intermedia.net>
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> Would it be possible to look at a much larger number of samples during  
> analyze,
> then look at the variation in those to generate a reasonable number of
> pg_statistic "samples" to represent our estimate of the actual  
> distribution?
> More datapoints for tables where the planner might benefit from it, fewer
> where it wouldn't.

	Maybe it would be possible to take note somewhere of the percentage of  
occurence of the most common value (in the OP's case, about 3%), in which  
case a quick decision can be taken to use the index without even looking  
at the value, if we know the most common one is below the index use  
threshold...

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