On 10/06/10 22:47, Craig James wrote:
> Postgres normally doesn't index NULL values even if the column is
> indexed, so it has to do a table scan when your query includes an IS
> NULL condition.
That was addressed in version 8.3. 8.3 and upwards can use an index for
IS NULL.
I believe the NULLs were stored in the index in earlier releases too,
they just couldn't be searched for.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com