Re: IS NOT DISTINCT FROM + Indexing

Jonathan S. Katz <jonathan.katz@excoventures.com> wrote:

> before embarking on something laborious (as even just indexing
> is nontrivial), I think it would be good to figure out how people
> are using IS [NOT] DISTINCT FROM and if there is interest in
> having it be indexable, let alone used in a JOIN optimization.
> It could become a handy tool to simplify the SQL in queries that
> are returning a lot of NULL / NOT NULL data mixed together.

To prevent subtle inconsistencies, I think we would need to limit
support to data types with a btree opclass which uses "=" as the
equality operator on indexes using that opclass (either by default
or explicitly).  That limitation would still allow a lot of useful
cases.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company