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

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(at)gmail(dot)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".

--
nathan