RE: connection pool sizing

From: Stephens, Chris <Chris.Stephens_at_adm.com>
Date: Wed, 16 Sep 2015 19:54:48 +0000
Message-ID: <883de46ad473442587757520d0b2f5cc_at_JRCEX13MB1.research.na.admworld.com>

These are excellent videos (as was the PDF supplied by Oyvind). RWP group does a good job of explaining why a large and/or varying size connection pool can be a problem and demonstrates the benefit of reducing the size of the connection pool and keeping the size constant.

I was looking for a rough estimate/formula for coming up with a decent initial pool size based on relevant factors. I think that would primarily be CPU/Core count but could include other variables.

At least now I’ll recognize the symptoms of a connection pool size problem and know what direction to head.

Thanks!
chris

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Mihajlo Tekic Sent: Monday, September 14, 2015 5:58 PM To: oyvind.isene_at_gmail.com
Cc: oracle-l <oracle-l_at_freelists.org> Subject: Re: connection pool sizing

Below are links to couple of videos, on the subject, that you could find very useful:

Real-World Performance - 13 - Large Dynamic Connection Pools - Part 1 https://www.youtube.com/watch?v=Oo-tBpVewP4

Real-World Performance - 14 - Large Dynamic Connection Pools - Part 2 https://www.youtube.com/watch?v=XzN8Rp6glEo

Regards,
Mihajlo Tekic

On Mon, Sep 14, 2015 at 3:25 PM, Øyvind Isene <oyvind.isene_at_gmail.com<mailto:oyvind.isene_at_gmail.com>> wrote: This is a topic covered by the Real World Performance Group; no one does it better explaining this. Here is one link to a recent preso I found by googling:

http://rwpt.hroug.hr/content/download/6547/107877/file/RWP2015%20part%20I.pdf

If you go to Open World, be sure to catch at least one of their sessions, it is probably the best infotainment you get there, especially if you have a taste for British sarcasm ;-) Also get in touch with your local user group and see if they have invited them for 2016.

2015-09-14 23:47 GMT+02:00 Martijn Bos <maboc_at_maboc.nl<mailto:maboc_at_maboc.nl>>: I think it more depends on the usage of the connections in the pool. If all your connections, out of the pool, are always busy it is probably wise to take numbers of CPU into account. If they are only used once in a while I would monitor connectionpool usage.

Best Regards,
Martijn

On 14-09-15 20:57, Stephens, Chris wrote:
> Are there general recommendations on initial connection pool sizing based on the number of CPU's available to a database?
>
> I keep seeing connection pools sized far (far!) beyond the number of CPU's and that doesn't make any sense to me.
>
> Chris
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Received on Wed Sep 16 2015 - 21:54:48 CEST