Arne Roland <A.Roland@xxxxxxxx> writes: > I want to examine the exhaustive search and not the geqo here. I'd expect the exhaustive search to give the plan with the lowest cost, but apparently it doesn't. I have found a few dozen different querys where that isn't the case. I attached one straight forward example. For the join of two partitions a row first approach would have been reasonable. Hmm. While the search should be exhaustive, there are pretty aggressive pruning heuristics (mostly in and around add_path()) that can cause us to drop paths that don't seem to be enough better than other alternatives. I suspect that the seqscan plan may have beaten out the other one at some earlier stage that didn't think that the startup-cost advantage was sufficient reason to keep it. It's also possible that you've found a bug. I notice that both plans are using incremental sort, which has been, um, rather buggy. Hard to tell without a concrete test case to poke at. regards, tom lane
