Re: index vs. seq scan choice?

From: PFC <lists(at)peufeu(dot)com>
To: "Steve Atkins" <steve(at)blighty(dot)com>, "PostgreSQL General" <pgsql-general(at)postgresql(dot)org>
Subject: Re: index vs. seq scan choice?
Date: 2007-05-25 08:09:17
Message-ID: op.tsvh9ra1cigqcu@apollo13
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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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