Re: An Idea for planner hints

"Christopher Kings-Lynne" <chris.kingslynne@gmail.com> writes:
> see.  Collecting the statistics thereafter isn't that hard, but there
> needs to be a way to not collect an exponential volume of statistics on
> all column combinations.

> You could collect them on all FK relationships - is that enough?

As somebody pointed out upthread, collecting these stats on FK
relationships is actually not very interesting: you already know
that the referenced side of the relationship is a unique column,
and so the selectivity stats of the referencing side are enough.
        regards, tom lane