Hi,
On 2020-04-11 15:53:11 -0400, James Coleman wrote:
> On Sat, Apr 11, 2020 at 2:01 PM Andres Freund <andres@anarazel.de> wrote:
> > > - If not, is there a way in that framework to know if the array expr
> > > has stayed the same through multiple evaluations of the expression
> > > tree (i.e., so you could expand and sort it just once)?
> >
> > No.
>
> Ok. Seems like it'd be likely to be interesting (maybe in other places
> too?) to know if:
> - Something is actually a param that can change, and,
> - When (perhaps by some kind of flag or counter) it has changed.
We do have the param logic inside the executor, which does signal which
params have changed. It's just independent of expression evaluation.
I'm not convinced (or well, even doubtful) this is something we want to
have at the expression evaluation level.
Greetings,
Andres Freund