Tim Kane <tim.kane@xxxxxxxxx> writes: > Is there a propensity for 9.2.4 to prefer a sort-merge-join, in place of a > hash join? Not particularly; I don't think there's any actual difference in the cost estimation equations between 9.2 and 9.3. The two plans you show are close enough in estimated cost that the ordering of their costs might be coming out differently just as a matter of random variation in statistics. It'd be worth double-checking the work_mem setting on both systems, though, as (IIRC) an undersized work_mem hurts the estimate for hashes more than for sorts. regards, tom lane
