On Sun, Jan 16, 2022 at 7:28 PM Peter Geoghegan <p...@bowt.ie> wrote: > > The current hash_mem_multiplier default is 1.0, which is a fairly > conservative default: it preserves the historic behavior, which is > that hash-based executor nodes receive the same work_mem budget as > sort-based nodes. I propose that the default be increased to 2.0 for > Postgres 15.
I don't have anything really profound to say here, but in the last year I did on a couple occasions recommend clients to raise hash_mem_multiplier to 2.0 to fix performance problems. During this cycle, we also got a small speedup in the external sorting code. Also, if the "generation context" idea gets traction, that might be another reason to consider differentiating the mem settings. -- John Naylor EDB: http://www.enterprisedb.com
