On Mon, Jun 29, 2020 at 10:20:14AM -0700, Peter Geoghegan wrote: > I have no reason to believe that the planner is any more or any less > likely to conclude that the hash table will fit in memory in v13 as > things stand (I don't know if the BufFile issue matters). > > In general, grouping estimates probably aren't very good compared to > join estimates. I imagine that in either v12 or v13 the planner is > likely to incorrectly believe that it'll all fit in memory fairly > often. v12 was much too permissive about what could happen. But v13 is > too conservative.
FYI, we have improved planner statistics estimates for years, which must have affected node spill behavior on many node types (except hash_agg), and don't remember any complaints about it. -- Bruce Momjian <br...@momjian.us> https://momjian.us EnterpriseDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee
