Re: Process and sessions overhead

From: Kevin Closson <>
Date: Tue, 8 Mar 2011 19:03:48 -0800 (PST)
Message-ID: <>

> I think that many severely underestimate how much productive work a single
>Oracle session process can do.

...that presumes processor efficiency. I would never question the capability of a foreground to busy a processor core--even without breaking a sweat. Let's not forget we are systems' people and "busy" CPU does not equate to valid work getting done.

...48 CPUs and 256GB memory...hmmm... that smells a lot like and 8-way AMD (ala Proliant DL785 with Istanbul Opterons?) or a 4 way AMD 6100 (MC) box? Please do let us know. I like to keep a feel for what folks are doing these days.

From: Greg Rahn <> To: "CRISLER, JON A (ATTCORP)" <> Cc:
Sent: Tue, March 8, 2011 11:16:59 AM
Subject: Re: Process and sessions overhead

Unfortunately this does not help. Describing hardware does not explain software requirements.

I dont mean to be difficult, but I think that many severely underestimate how much productive work a single Oracle session process can do.

However, you could win me over by providing scaling data that shows connections and application throughput rates and txn times... Might you have done such tests and collected the data?

On Tue, Mar 8, 2011 at 11:05 AM, CRISLER, JON A (ATTCORP) <> wrote:
> I have been asked this question many times, but perhaps if mention that the
>server has 48 cpu and 256gb of memory, and 10 tb of disk, it might give you an
>idea of the load that is expected.
> -----Original Message-----
> From: Greg Rahn []
> Sent: Tuesday, March 08, 2011 2:03 PM
> Cc:
> Subject: Re: Process and sessions overhead
> Because curiosity is killing me, what is the requirement to have 1000
> sessions, let alone 2000? That just seems broken to me.
> The reason I bring this up is because there isn't just potential
> issues at the database level, most OS perform much worse with that
> many processes. Think about the time sharing model when there are
> 2000 processes to schedule.
> I believe that Andrew Holdsworth (my boss) is doing an
> "over-processed" demo as part of the IOUG tour which is based off the
> one he did for OOW10.
> Maybe someone on this list has attended one and can comment.
> On Tue, Mar 8, 2011 at 8:48 AM, CRISLER, JON A (ATTCORP) <>
>> What is the memory overhead of increasing processes and sessions ? Say I
>> current have 1000 sessions and I want to increase that to 2000 sessions: how
>> much extra memory would I use assuming no additional processes sessions are
>> really used ?

Greg Rahn

Received on Tue Mar 08 2011 - 21:03:48 CST

Original text of this message