Re: Statistics Import and Export

I still think that we could just declare the function strict, if we
use the variadic-any approach.  Passing a null in any position is
indisputable caller error.  However, if you're allergic to silently
doing nothing in such a case, we could have pg_set_attribute_stats
check each argument and throw an error.  (Or warn and keep going;
but according to the design principle I posited earlier, this'd be
the sort of thing we don't need to tolerate.)