Viktor Leis <leis(at)in(dot)tum(dot)de> writes:
> I think it would be a good start to distinguish between nested loop
> joins with and without a index.
We do.
> In my opinion, the latter should simply NEVER be chosen.
So, if you're given a query with a non-equality join condition
that doesn't match any index on either table, you think the planner
should just fail? This is not realistic. Certainly nestloop with
inner seqscan is likely to be slow, but that's already reflected
in the cost estimates.
regards, tom lane