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.
--
regards,
Andrei Lepikhov
Postgres Professional
