Re: BUG #1252: Optimization of SELECT for NOT NULL case

On Wed, Sep 15, 2004 at 23:29:43 +0300,
  Alexander Kirpa <postgres@bilteks.com> wrote:
> On 15 Sep 2004, at 12:21, Bruno Wolff III wrote:
>
> Regarding your point of view possible exist reason for remove
> optimization for case like below
> SELECT count(*) from x where id>1 AND id<0
> I basically don't see any significant difference in optimization
> for "id IS NULL" and "id>1 AND id<0"

People generally know whether or not a table is NOT NULL and aren't very
likely to write queries searching for NULL values in such a table.

A general constraint handler would be useful (for example in handling
partitions of data sets), but just doing it for NOT NULL seems like it
would be a net loss.