Re: Has gen_random_uuid() gotten much slower in v17?

On 9/11/24 12:47, David Mullineux wrote:
> Good idea. Thanks.    I did check. It's not enabled by default but just
> in case I did another build. This time explicitly defining --disable-
> debug and --disable-cassert. And I tested. Still slower than old versions.
>

4.5 seconds is very surprising.

on my machine:

postgres=# explain (analyze, costs off) select gen_random_uuid() from
generate_series(1, 50000);
QUERY PLAN

----------------------------------------------------------------------------------
Function Scan on generate_series (actual time=3.507..123.492
rows=50000 loops=1)
Planning Time: 0.031 ms
Execution Time: 125.481 ms
(3 rows)

postgres=# select version();
version

----------------------------------------------------------------------------------------------
PostgreSQL 18devel on x86_64-pc-linux-gnu, compiled by gcc (Debian
12.2.0-14) 12.2.0, 64-bit

pg_config | grep CONFIGURE
CONFIGURE = '--enable-cassert' '--enable-debug' '--with-python'
'CFLAGS=-ggdb -Og -g3 -fno-omit-frame-pointer' '--prefix'
'/postgres/pgenv/master'

> This feels like a build configuration problem. Just can't put my finger
> on it yet.

Why not using a profiler to see what's going on?