"ldh@xxxxxxxxxxxxxxxxxx" <ldh@xxxxxxxxxxxxxxxxxx> writes: > One question that popped up in my head. hash_mem_multiplier is an upper-bound right: it doesn't reserve memory ahead of time correct? So there is no reason for me to spend undue amounts of time fine-tuning this parameter? If I have work_mem to 521MB, then I can set hash_mem_multiplier to 8 and should be OK. This doesn't mean that every query will consume 4GB of memory. Yeah, I wouldn't sweat over the specific value. The pre-v13 behavior was effectively equivalent to hash_mem_multiplier = infinity, so if you weren't having any OOM problems before, just crank it up. regards, tom lane