Re: Index Usage using IN - Mailing list pgsql-performance

"Jeffrey W. Baker" <jwbaker@acm.org> writes:
> On Thu, 2006-02-02 at 09:12 +1300, Ralph Mason wrote:
>> Select ID from TableA where ID not IN ( Select ID from Table B)

> Have you considered this:

> SELECT ID from TableA EXCEPT Select ID from Table B

Also, increasing work_mem might persuade the planner to try a hashed
subplan, which'd be a lot better than what you have.  Note that it's
quite unlikely that indexes are going to help for this.

            regards, tom lane