Re: [EXTERNAL] Re: Performance down with JDBC 42

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(dot)albe(at)cybertec(dot)at>
> Sent: Saturday, November 4, 2023 11:07 PM
> To: Abraham, Danny <danny_abraham(at)bmc(dot)com>; psql-performance <pgsql-performance(at)postgresql(dot)org>
> 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