On 11/29/22 03:36, Alvaro Herrera wrote:
On 2022-Nov-28, Mladen Gogala wrote:
As for JIT, I've recently asked that question myself. I was told that
PostgreSQL with LLVM enabled performs approximately 25% better than without
it.
Hmm, actually, normally you're better off turning JIT off, because it's
very common to diagnose cases of queries that become much, much slower
because of it. Some queries do become faster, but it's not a wide
margin, and it's not a lot. There are rare cases where JIT is
beneficial, but those tend to be queries that take upwards of several
seconds already.
IMO it was a mistake to turn JIT on in the default config, so that's one
thing you'll likely want to change.
Hmmm, I think I will run pgbench with and without JIT on and see the difference.
--
Mladen Gogala
Database Consultant
Tel: (347) 321-1217
https://dbwhisperer.wordpress.com