Re: Postgres 15 SELECT query doesn't use index under RLS

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alexander Okulovich <aokulovich@stiltsoft.com>
Cc: pgsql-performance@postgresql.org
Date: 2023-10-26T14:09:37Z
Lists: pgsql-performance
Alexander Okulovich <aokulovich@stiltsoft.com> writes:
> I've attempted to reproduce this on my PC in Docker from the stage 
> database dump, but no luck. The first query execution on Postgres 15 
> behaves like on the real stage, but subsequent ones use the index.

Can you force it in either direction with "set enable_seqscan = off"
(resp. "set enable_indexscan = off")?  If so, how do the estimated
costs compare for the two plan shapes?

> Also, 
> they execute much faster. Looks like the hardware and(or) the data 
> structure on disk matters.

Maybe your prod installation has a bloated index, and that's driving
up the estimated cost enough to steer the planner away from it.

			regards, tom lane