Re: Queueing Theory in Oracle
- From: Ls Cheng <exriscer@xxxxxxxxx>
- To: Jonathan Lewis <jonathan@xxxxxxxxxxxxxxxxxx>
- Date: Tue, 11 Mar 2014 21:23:10 +0100
Hi
I thought the reasons of getting normal data distribution was probably how
the test is run. Since it's a constant 300/420 users running probably 30 or
40 different SQL statements ( I dont know how many are there in a TPC
test), the server was only 18% loaded, the database metric I used were
gathered from v$sysmetrc (so I have metric rates in per second unit
gathered every minute), all mix together the distribution I got was normal,
I even took the sample data and used Cary's mdist.pl to see if the data was
exponentially distributed and all were rejected. After checking that and
think a bit then I think the normal data distribution is expected, if I am
running 16 TPC transactions per second and there are few in the lower side
a few in the higher side and most were in the middle then of course it's a
normal data distribution, why should I expect it to be exponentially
distributed?
I used TPS as arrival rate and little's law to get the service time (used
host cpu as utilization)
system utilization = (arrival rate * service time) / number of servers
The service time was normal distributed as well
So using the TPC test sample data, the formulas I could find (I have
downloaded probably 20 PPT from 7 or 8 universities statistics courses)
they just dont "glue" together in an Oracle Database and that is why I am
asking if anyone has successfully used queueing theory in Oracle so at
least I can get some points and see what I am dong wrong :-)
Thanks
On Tue, Mar 11, 2014 at 9:07 PM, Jonathan Lewis <jonathan@xxxxxxxxxxxxxxxxxx
> wrote:
>
>
> That's an interesting observation - but (viewed from the outside) I would
> be a little suspicious that the normal distribution was an artifact of the
> data generation mechanism and the test mechanism.
>
>
>
> Regards
> Jonathan Lewis
> http://jonathanlewis.wordpress.com
> @jloracle
> ------------------------------
> *From:* Ls Cheng [exriscer@xxxxxxxxx]
> *Sent:* 11 March 2014 20:01
> *To:* Karl Arao
> *Cc:* Jonathan Lewis; Oracle Mailinglist
>
> *Subject:* Re: Queueing Theory in Oracle
>
>
> I ran last week a couple of TPC load with 300 and 420 users then I used
> both transaction per second and logical reads per second metric and both
> showed normal data distribution and that is why I have doubts of how to use
> queueing theory in Oracle.
>
> From your paper was you able to predict the change from v1 to x2 without
> run the actual test? Then run the test and validate the prediction?
>
>
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