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 |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general pgsql-www |
> 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...
From | Date | Subject | |
---|---|---|---|
Next Message | Cyril VELTER | 2007-05-25 08:17:34 | Re: Winsock error 10035 while trying to upgrade from 8.0 to 8.2 |
Previous Message | Michael Harris (BR/EPA) | 2007-05-25 06:08:46 | ERROR: cache lookup failed for type 0 |
From | Date | Subject | |
---|---|---|---|
Next Message | John D. Burger | 2007-05-25 12:55:24 | Re: index vs. seq scan choice? |
Previous Message | Steve Atkins | 2007-05-25 04:25:23 | Re: index vs. seq scan choice? |