Manuel Weitzman <manuelweitzman@gmail.com> writes:
> I've written a very naive (and crappy) patch to show how adding
> memorization to get_actual_variable_range() could help the planner on
> scenarios with a big number of joins.
So ... the reason why there's not caching of get_actual_variable_range
results already is that I'd supposed it wouldn't be necessary given
the caching of selectivity estimates that happens at the RestrictInfo
level. I don't have any objection in principle to adding another
caching layer if that one's not working well enough, but I think it'd
be wise to first understand why it's needed.
regards, tom lane