On Wed, Dec 25, 2024 at 11:34 AM Andrei Lepikhov <lepi...@gmail.com> wrote: > I have a couple of notes. > 1. The nulling_relids provides us sensible information about possible > nulls inside the input. We are not using it to estimate the number of > such nulls for now. Does Your idea consist of obtaining 'clear' > statistics and reusing nulling_relids knowledge somewhere later?
Are you referring to the nullfrac estimates? A RelOptInfo's nulling_relids records all above outer joins that can null this rel. However, I cannot see how it helps with nullfrac. > 2. It is ok for Vars. But what about expressions? We use equal() in > distinct, MCV and dependencies modules. Do we need to remove nulls > before using extended statistics as a general rule? AFAIU, the expressions in extended statistics are not decorated with any nullingrels bits, are they? Thanks Richard
