On Fri, Dec 22, 2023 at 7:24 PM Andrei Lepikhov <a.lepik...@postgrespro.ru> wrote: > On 22/12/2023 11:48, Alexander Korotkov wrote: > > > Because we must trust all predictions made by the planner, we just > > > choose the most trustworthy path. According to the planner logic, it is > > > a path with a smaller selectivity. We can make mistakes anyway just > > > because of the nature of estimation. > > > > Even if we need to take selectivity into account here, it's still not > > clear why this should be on top of other logic later in add_path(). > I got your point now, thanks for pointing it out. In the next version of > the patch selectivity is used as a criteria only in the case of COSTS_EQUAL.
It looks better now. But it's hard for me to judge these heuristics in add_path(). Tom, what do you think about this? ------ Regards, Alexander Korotkov
