Re: Strange behaviour of SELECT ... IN

On Wed, Jun 26, 2002 at 04:00:08PM -0400, Jorge Sarmiento wrote:
> uh...
>
> the first one is an INDEX SCAN, the second one a SEQUENTIAL SCAN.
>
> number of rows in table has nothing to do...

Wrong. The number of rows has everything to do with it. If the number of
rows exceeds 50% of the table, a sequential scan is faster than an index
scan.

You can use enable_seq_scan=off to force it. Let us know if the index scan
is actually significantly faster.

Oh, you did use VACUUM ANALYZE right?

--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> There are 10 kinds of people in the world, those that can do binary
> arithmetic and those that can't.