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DB Maximum Connections & rule of thumb

From: Yogesh <ytalreja_at_comcast.net>
Date: 13 Dec 2004 16:10:47 -0800
Message-ID: <1102983047.722596.200550@z14g2000cwz.googlegroups.com>

Sybrand Bakker wrote:
> On 3 Nov 2004 14:03:42 -0800, ytalreja_at_comcast.net (Y) wrote:
>
> >Folks,
> >
> > We are running 6 instances of a proprietary application server
> >against an Oracle8 instance with a connection pool of 16 each (for a
> >total of 96 connections). This is running on a dual proc Sun server
> >with 1 GB of memory As our volumes have ramped up, we need to
increase
> >the number of connections in the pool and the related parameters in
> >Oracle's config files.
>
> Why do you *assume* you need to increase the number of connections?
> You have a connection pool, remember?
> With 96 connections you typically don't need any pool at all!

The application is a consumer application and will very soon need to support several thousand users over the internet. We are already seeing connections timing out since the queue waiting for the connections in the connection pool is too long.

>
> All users to the database go through these App
> >Servers/connection pools.
> >
> > I believe I would need to increase the queuesize in
listener.ora'
>
> Frankly I have NEVER used that parameter, and I am running with
> hundreds of simultaneous connections.
>
> >file and the SESSIONS/PROCESSES parameters in init.ora file. Are
there
> >any other parameters I need to change?
>
> SEMMNI and SEMMNS on Unix come to mind. The number of semaphores
> should equal (per database!) 2 * #processes + 10.
>
> >
> > I would like to know if there is a formula to determine a "safe"
> >limit for bumping these up; i.e. if there is a rule of thumb for
> >correlating maximum number of these parameters with the # of CPUs/
> >memory size. I do realize that if I bump these up too high, I will
run
> >into the Unix limit of max. # of processes, but that typically
exceeds
> >1024.
>
>
> Typically you shouldn't indiscriminately 'bump' any parameters at all
> without being capable to demonstrate lack of resources and/or error
> messages.
> 'Bumping up' usually results in relocating the problem to the O/S

That's why I wanted to know the correlation, or the rule of thumb. We are also upgrading the hardware.
> >

Yogesh
>
> --
> Sybrand Bakker, Senior Oracle DBA
Received on Mon Dec 13 2004 - 18:10:47 CST

Original text of this message

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