Re: Reduce "Var IS [NOT] NULL" quals during constant folding

On Wed, Aug 20, 2025 at 11:11 PM Nathan Bossart
<nathandbossart@gmail.com> wrote:
> On Wed, Aug 20, 2025 at 10:29:03AM +0900, Richard Guo wrote:
> > On Wed, Aug 20, 2025 at 2:38 AM Nathan Bossart <nathandbossart@gmail.com> wrote:
> >> There is still an open item for this one, but it's not clear whether we are
> >> planning to do anything about this for v18, especially since nobody has
> >> shown measurable performance impact.  Does anyone want to argue for
> >> addressing this for v18, or shall we close the open item as "Won't Fix"?

> > I don't think we're likely to do anything about this for v18.
> > Actually, I still doubt that the extra table_open call brings any
> > measurable performance impact, especially since the lock is already
> > held and the relation is likely already present in the relcache.
> >
> > Also, I still don't think moving the expansion of virtual generated
> > columns to the rewriter (as Tom proposed) is a better idea.  It turned
> > out to have several problems that need to be fixed with the help of
> > PHVs, which is why we moved the expansion into the planner.

> Okay.  I have marked the v18 open item as "Won't Fix".

Thank you for helping with this.

Thanks
Richard