"henk de wit" <henk53602@xxxxxxxxxxx> writes: > Naively I would say that a planner > would have to be smart enough to see this by itself? We got rid of direct tests for redundant WHERE clauses a long time ago (in 7.4, according to some quick tests I just made). They took a lot of cycles and almost never accomplished anything. Since you have two redundant tests, the selectivity is being double-counted, leading to a too-small rows estimate and a not very appropriate choice of join plan. FWIW, CVS HEAD does get rid of the duplicate conditions for the common case of mergejoinable equality operators --- but it's not explicitly looking for duplicate conditions, rather this is falling out of a new method for making transitive equality deductions. regards, tom lane
