Re: EXISTS vs IN vs OUTER JOINS

Tom Lane wrote:
> Joe Conway <mail@joeconway.com> writes:
> > I wonder if "[NOT] IN (subselect)" could be improved with a hash table in
> > similar fashion to the hash aggregate solution Tom recently implemented?
>
> It's being worked on ;-)
>
> http://archives.postgresql.org/pgsql-hackers/2002-11/msg01055.php
>
> Assuming I get this done, the conventional wisdom that "EXISTS
> outperforms IN" will be stood on its head --- unless we add planner code
> to try to reverse-engineer an IN from an EXISTS, which is something I'm
> not really eager to expend code and cycles on.

I am looking forward to removing _that_ FAQ item.  :-)

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