Re: 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
>
>