Re: Big performance slowdown from 11.2 to 13.3
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: "ldh@laurent-hasson.com" <ldh@laurent-hasson.com>
Cc: Peter Geoghegan <pg@bowt.ie>, David Rowley <dgrowleyml@gmail.com>,
Justin Pryzby <pryzby@telsasoft.com>,
"pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
Date: 2021-07-25T18:08:27Z
Lists: pgsql-performance
"ldh@laurent-hasson.com" <ldh@laurent-hasson.com> writes: > As a user of PG, we have taken pride in the last few years in tuning the heck out of the system and getting great performance compared to alternatives like SQLServer. The customers we work with typically have data centers and are overwhelmingly Windows shops: we won the battle to deploy a complex operational system on PG vs SQLServer, but Linux vs Windows was still a bridge too far for many. I am surprised that this limitation introduced after V11 hasn't caused issues elsewhere though. Maybe it has, but you're the first to report the problem, or at least the first to report it with enough detail to trace the cause. I've pushed a fix that removes the artificial restriction on work_mem times hash_mem_multiplier; it will be in next month's 13.4 release. You'll still need to increase hash_mem_multiplier to get satisfactory performance on your workload, but at least it'll be possible to do that. regards, tom lane
Commits
-
Get rid of artificial restriction on hash table sizes on Windows.
- b154ee63bb65 14.0 landed
- 2b8f3f5a7c0e 13.4 landed
- 28d936031a86 15.0 landed