Re: Incorrect information in src/backend/optimizer/README - Mailing list pgsql-hackers

From Etsuro Fujita
Subject Re: Incorrect information in src/backend/optimizer/README
Date
Msg-id 000b01ce995d$8f102010$ad306030$@lab.ntt.co.jp
Whole thread Raw
In response to Re: Incorrect information in src/backend/optimizer/README  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]

> "Etsuro Fujita" <fujita.etsuro@lab.ntt.co.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




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