Thread: Joining between large & small tables?
Given a large large large table A and a small small temp table B is there any benefit to doing SELECT * FROM a JOIN b USING (somecol) vs SELECT * FROM b JOIN a USING (somecol)?
When you just want the intersection...
> On Jul 13, 2020, at 7:39 PM, Wells Oliver <wells.oliver@gmail.com> wrote: > > Given a large large large table A and a small small temp table B is there any benefit to doing SELECT * FROM a JOIN b USING(somecol) vs SELECT * FROM b JOIN a USING (somecol)? > > When you just want the intersection... No, planner will figure out how to join based on stats, not order. (With default planner options; there are ways to workaround that in the rare case that the planner can't figure out the best way.)
On Mon, Jul 13, 2020 at 6:40 PM Wells Oliver <wells.oliver@gmail.com> wrote:
Given a large large large table A and a small small temp table B is there any benefit to doing SELECT * FROM a JOIN b USING (somecol) vs SELECT * FROM b JOIN a USING (somecol)?
David J.