Re: seq scan instead of index scan

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: "Karl Larsson" <karl(dot)larsson47(at)gmail(dot)com>, <pgsql-performance(at)postgresql(dot)org>
Subject: Re: seq scan instead of index scan
Date: 2009-12-17 23:29:14
Message-ID: 4B2A6A6A020000250002D750@gw.wicourts.gov
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Karl Larsson <karl(dot)larsson47(at)gmail(dot)com> wrote:

> When I make a subquery Postgres don't care about my indexes and
> makes a seq scan instead of a index scan. Why?

> Total runtime: 0.133 ms

Because it thinks that it's faster that way with the particular data
you now have in your tables. With more data, it might think some
other plan is faster. It's running in less than 1/7500 second --
how sure are you that it would be significantly faster another way?

-Kevin

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