On Sat, Apr 25, 2020 at 5:41 PM David Rowley <dgrowleyml@gmail.com> wrote:
>
> On Sun, 26 Apr 2020 at 00:40, Tomas Vondra <tomas.vondra@2ndquadrant.com> wrote:
> > This reminds me our attempts to add bloom filters to hash joins, which I
> > think ran into mostly the same challenge of deciding when the bloom
> > filter can be useful and is worth the extra work.
>
> Speaking of that, it would be interesting to see how a test where you
> write the query as IN(VALUES(...)) instead of IN() compares. It would
> be interesting to know if the planner is able to make a more suitable
> choice and also to see how all the work over the years to improve Hash
> Joins compares to the bsearch with and without the bloom filter.
It would be interesting.
It also makes one wonder about optimizing these into to hash
joins...which I'd thought about over at [1]. I think it'd be a very
significant effort though.
James
[1]: https://www.postgresql.org/message-id/CAAaqYe_zVVOURfdPbAhssijw7yV0uKi350gQ%3D_QGDz7R%3DHpGGQ%40mail.gmail.com