Simon Riggs <simon@2ndquadrant.com> writes:
> Say if cost of best plan >= N then recheck query for strangeness. If
> anything found, re-plan query.
Whatever makes you think that would be useful?
The usual result of undetected duplicate WHERE clauses is an
*underestimate* of runtime, not an overestimate (because it thinks
too few tuples will be selected).
regards, tom lane
