Re: Yet another "Why won't PostgreSQL use my index?" - Mailing list pgsql-general

From Gregory Wood
Subject Re: Yet another "Why won't PostgreSQL use my index?"
Date
Msg-id 002501c2187e$58d47620$7889ffcc@comstock.com
Whole thread Raw
In response to Re: Yet another "Why won't PostgreSQL use my index?"  (Stephan Szabo <sszabo@megazone23.bigpanda.com>)
List pgsql-general
I am assuming that this query is retrieving what you are looking for:

SELECT pg_statistic.* FROM pg_statistic JOIN pg_attribute ON
starelid=attrelid WHERE attname='idx_siteid';

I've attached the results so they don't wrap quite as badly.

Also included is a count for the individual idx_siteid values, if that might
be useful to see how they are distibuted.

Greg

----- Original Message -----
From: "Stephan Szabo" <sszabo@megazone23.bigpanda.com>
To: "Gregory Wood" <gregw@com-stock.com>
Cc: "PostgreSQL-General" <pgsql-general@postgresql.org>
Sent: Thursday, June 20, 2002 12:19 PM
Subject: Re: [GENERAL] Yet another "Why won't PostgreSQL use my index?"


>
> On Thu, 20 Jun 2002, Gregory Wood wrote:
>
> > Trying to use a single column index on a somewhat large table (1.9M
rows),
> > and PostgreSQL really doesn't want to. It estimates the number of rows
at
> > 12749 (actual 354), which is only .6% of the table... well within
reasonable
> > index range I would think. And yes, I've run an analyze on the table.
>
> It might be interesting to figure out why it's over estimating the rows
> so badly.  What do the statistics in pg_statistic for that
> relation/attribute look like?
>

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