Gregory Stark wrote: > "Julian Mehnle" <julian@xxxxxxxxxx> writes: > > I actually do have constraints on all the partitions, e.g. for week > > 34: [...] > > > > Shouldn't this be enough to give the query planner a clue that it > > only has to join the "email" and "email_extras" tables' partitions > > pair-wise, as opposed to cross-joining them? > > Ah, well, this falls under "The optimizer is a bit dumb about > partitioned tables". It only looks at the constraints to compare > against your WHERE clause. It doesn't compare them against the > constraints for other tables to see if they're partitioned on the same > key and therefore can be joined table-by-table. > > I want 8.4 to be cleverer in this area but there's a ton of things it > has to learn. That would be great. So there's nothing that can be done about it right now, apart from manually combining separate SELECTs for each partition using UNION? Julian.
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