Timothy Garnett <tgarnett@panjiva.com> writes: > Is there some way to tell the planner that unless it's guaranteed by a > constraint or some such it shouldn't guess that the selectivity of a > filter/anti-join is 1 row (e.g. minimum to consider is 2 rows unless it's > guaranteed to be 1 row) or somehow otherwise make it more conservative > around the worst case possibilities.
There's been some discussion in that area, but it's a hard problem to solve in general, and especially so if you'd like to not break a ton of queries that work nicely today.
