-----Message d'origine-----
De : davecramer@gmail.com [mailto:davecramer@gmail.com] De la part de Dave Cramer
Envoyé : mardi 9 octobre 2012 13:06
À : BENHAMOU Mathieu
Cc : pgsql-jdbc@postgresql.org; ROUX Christian; CREMIEUX Alain; FORGEARD Thierry; MARCHAND Franck
Objet : Re: [JDBC] drop in performance using jdbc driver version 9
Can you be specific about which meta data calls you are making ?
Test case ?
Dave Cramer
dave.cramer(at)credativ(dot)ca
http://www.credativ.ca
On Tue, Oct 9, 2012 at 3:44 AM, BENHAMOU Mathieu <mathieu.benhamou@cegedim-srh.com> wrote:
> Hello,
>
>
>
> We have been using postgreSQL for several years and we have just
> upgraded the jdbc driver (along with the db server) to version 9. As a
> result, we are getting poor performance with the new configuration:
> operations that took about 10 seconds using
> postgresql-8.4-701.jdbc4.jar take more than 2 minutes now.
>
>
>
> To be more accurate, our application relies on some kind of init
> function that uses select queries involving metadata and ordinary data.
>
> 1. This operation takes about 12 seconds when our application is
> running with postgresql-8.4-701.jdbc4.jar. It also takes 12 or 15
> seconds with postgresql-9.0dev-800.jdbc3.jar.
>
> However, it takes more than 120(!) seconds using
> postgresql-9.0-801.jdbc3.jar or later versions.
>
>
>
> 2. Our guess is that metadata functions have become much slower since
> 9.0-801. We also found that many more requests are generated by the
> metadata functions. About 1200 request are sent to the database server
> when running postgresql-8.4-701.jdbc4.jar, more than 2000 when running
> postgresql-9.1-902.jdbc4.jar.
>
> Methods such as get getIndexInfo() from AbstractJdbc2DatabaseMetaData
> seem to have changed a lot, but there are probably other major changes.
>
>
>
> 3. Can you confirm that changes in the metadata functions of the JDBC
> driver might explain the drop in performance ?
>
> Is there any workaround that would save us from major surgery in our code ?
>
> Can we use postgresql-9.0dev-800.jdbc3.jar instead of later versions ?
>
> Is it safe to use postgresql-8.4-701.jdbc4.jar against a 9.0 server ?
>
>
>
> Thanks for your help.
>
>
>
> Best regards,
>
>
>
> Mathieu Benhamou
>
> CEGEDIM-SRH
>
>