On Sun, 2020-09-06 at 23:21 +0200, Tomas Vondra wrote: > I've tested the costing changes on the simplified TPC-H query, on two > different machines, and it seems like a clear improvement.
Thank you. Committed. > So yeah, the patched costing is much closer to sort (from the point > of > this cost/duration metric), although for higher work_mem values > there's > still a clear gap where the hashing seems to be under-costed by a > factor > of ~2 or more. There seems to be a cliff right after 4MB. Perhaps lookup costs on a larger hash table? Regards, Jeff Davis