Re: [PoC] Reducing planning time when tables have many partitions

On Wed, 9 Apr 2025 at 17:38, Amit Langote <amitlangote09@gmail.com> wrote:
> Still, maybe a tiny tweak to the last line could help steer readers
> right without diving into storage. How about:
>
> Most operations on EquivalenceClasses should ignore child members,
> which are stored separately from normal members.

I think the only part of the current text that makes me slightly
uncomfortable is the "ignore child members".  I don't mind your text,
but it does introduce detail about how the members are stored, which
isn't there before.

I think the "ignore child members" part could be fixed with:

--- a/src/backend/optimizer/README
+++ b/src/backend/optimizer/README
@@ -902,7 +902,7 @@ contain the equivalent child-relation variables or
expressions.  These
 members are *not* full-fledged members of the EquivalenceClass and do not
 affect the class's overall properties at all.  They are kept only to
 simplify matching of child-relation expressions to EquivalenceClasses.
-Most operations on EquivalenceClasses should ignore child members.
+Most operations on EquivalenceClasses needn't look at child members.

Would that be ok?

David