Am 05.11.23 um 17:20 schrieb Abraham, Danny:
Thanks Laurenz,
Traced two huge plans. They differ.
The fast one does use Materialize and Memoize (the psql).
Is there something in JDBC 42 that blocks these algoruthms?
*maybe* the driver changed some settings. You can check it with
select name, setting from pg_settings where name ~ 'enable';
using the JDBC-connection.
Regards, Andreas
Thanks again
Danny
-----Original Message-----
From: Laurenz Albe <laurenz.albe@xxxxxxxxxxx>
Sent: Saturday, November 4, 2023 11:07 PM
To: Abraham, Danny <danny_abraham@xxxxxxx>; psql-performance <pgsql-performance@xxxxxxxxxxxxxx>
Subject: [EXTERNAL] Re: Performance down with JDBC 42
On Sat, 2023-11-04 at 19:08 +0000, Abraham, Danny wrote:
Asking for help with a JDBC related issue.
Environment: Linux 7.9 PG 14.9 , very busy PG Server.
A big query - 3 unions and about 10 joins runs :
- 70ms on psql , DBeaver with JDBC 42 and in our Server using old
JDBC 9.2
- 2500 ms in our Server using new JDBC 42 driver. ( and this is
running many times)
Question: Is there a structured way to identify optimization setup ( Planner Method s ) changes?
Are there any known changes specific to JDBC 42.
What I would do is enable auto_explain and look at the execution plan when the statement is run by the JDBC driver. Then you can compare the execution plans and spot the difference.
Yours,
Laurenz Albe
--
Andreas Kretschmer - currently still (garden leave)
Technical Account Manager (TAM)
www.enterprisedb.com
