Re: Big performance slowdown from 11.2 to 13.3 - Mailing list pgsql-performance

From Tom Lane
Subject Re: Big performance slowdown from 11.2 to 13.3
Date
Msg-id 543673.1627442152@sss.pgh.pa.us
Whole thread Raw
In response to RE: Big performance slowdown from 11.2 to 13.3  ("ldh@laurent-hasson.com" <ldh@laurent-hasson.com>)
Responses Re: Big performance slowdown from 11.2 to 13.3  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
"ldh@laurent-hasson.com" <ldh@laurent-hasson.com> writes:
> One question that popped up in my head. hash_mem_multiplier is an upper-bound right: it doesn't reserve memory ahead
oftime correct? So there is no reason for me to spend undue amounts of time fine-tuning this parameter? If I have
work_memto 521MB, then I can set hash_mem_multiplier to 8 and should be OK. This doesn't mean that every query will
consume4GB 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



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