Re: Index ignored with "is not distinct from", 8.2 beta2 - Mailing list pgsql-hackers

On Mon, Nov 06, 2006 at 09:10:40PM -0500, JEAN-PIERRE PELLETIER wrote:
> I understand that the planner doesn't use indexes for IS NOT DISTINCT FROM,
> but it would
> be good because "is not distinct from" is very useful when you have nulls
> but don't want to use three value logic.

The main issue is that currently indexes cannot be used to find NULLs
in a table. Patches have been created that cover most index types, but
it's not part of the main distribution.

Partial indexes can be a solution to the "x IS NULL" clauses.

Hope this helps,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.