Well, you're obviously right - I didn't know this. I guess I've found
that the index is not used for null values, and deduced somehow that
NULL values are not stored in the index.
Thanks, it's nice to find out a 'bug' before it's too late :-)
regards
Tomas
> Are you sure NULL values are not stored? btree, gist and bitmap index
> and search for NULL values.
>
> select amname, amindexnulls, amsearchnulls from pg_am;
>
> amname | amindexnulls | amsearchnulls
> --------+--------------+---------------
> btree | t | t
> hash | f | f
> gist | t | t
> gin | f | f
> bitmap | t | t
> (5 rows)
>
>
> Sincerely yours,
> Vladimir Sitnikov