Re: Deterioration in performance when query executed in multi threads

Thanks Ken. I am going to test with different pool sizes and see if I see any improvements.
Are there other configuration options I should look like? I was thinking of playing with shared_buffer.

Thanks,
Anne

-----Original Message-----
From: ktm(at)rice(dot)edu [mailto:ktm(at)rice(dot)edu]
Sent: Wednesday, May 01, 2013 9:27 AM
To: Anne Rosset
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] Deterioration in performance when query executed in multi threads

On Wed, May 01, 2013 at 04:07:55PM +0000, Anne Rosset wrote:
> Hi Ken,
> Thanks for your answer. My test is actually running with jboss 7/jdbc and the connection pool is defined with min-pool-size =10 and max-pool-size=400.
>
> Why would you think it is an issue with the connection pool?
>
> Thanks,
> Anne
>

Hi Anne,

You want to be able to run as many jobs productively at once as your hardware is capable of supporting. Usually something starting a 2 x number of CPUs is best.
If you make several runs increasing the size of the pool each time, you will see a maximum throughput somewhere near there and then the performance will decrease as you add more and more connections. You can then use that sweet spot.
Your test harness should make that pretty easy to find.

Regards,
Ken