Re: Incorrect information in src/backend/optimizer/README

> From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]

> "Etsuro Fujita" <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp> writes:
> > ISTM the README contains incorrect information and requires revision
> > to reflect the current code. Please find attached a patch. ISTM the
> > patch needs to be applied to all active branches.
>
> This patch isn't an improvement, since grouping_planner doesn't have anything
> to do with constant quals at all. In modern releases, that's dealt with by
> create_gating_plan inside create_plan().

OK

> I remember looking at this text when I redid query_planner's API a few days
> ago and electing not to change it just then. I'm a bit inclined to just
remove
> both references to constant quals from this overview, since they're now taken
> care of at much lower levels --- query_planner itself has nothing to do with
> that processing. Alternatively, if we do want to discuss constant quals
> somewhere in here, maybe it needs to be in a separate subsection. I'm not
sure
> we need anything though. Constant quals are now handled just like other quals
> up till the last moment in createplan.c, where they're split out and put in
> a separate gating Result node just above where they would otherwise have been.

+1 for removing both of the references from the overview.

Thanks,

Best regards,
Etsuro Fujita