Re: ERROR: failed to build any 4-way joins

I wrote:
> I guess we need a hack
> to treat empty outer join conditions specially.

Actually, it can happen with non-empty join conditions too, if the join
condition doesn't mention the outer side; for instance, using your
example

explain SELECT * from fooview fv1
   LEFT OUTER JOIN fooview fv2 on fv2.a_for_max_b < 10;

So my original thoughts of a narrow special case for "OUTER JOIN ON TRUE"
went up in smoke, and I ended up just having have_relevant_joinclause()
troll for relevant outer joins all the time.  This probably isn't going
to cost enough planning time to matter, anyway.

            regards, tom lane