Re: Testing Direct I/O
- From: Mladen Gogala <gogala@xxxxxxxxxxxxx>
- To: somckit.khemmanivanh@xxxxxxxxxxxxxxxx
- Date: Mon, 13 Feb 2006 19:14:18 -0500
On 02/13/2006 06:11:47 PM, Khemmanivanh, Somckit wrote:
>
> I saved and executed a few benchmark SQL statements pre-direct i/o, is
> this enough? Can I simply re-exexcute these benchmark statements?
Yes you can. Make sure those statements are laced with several "TRUNCATE" and
"DROP" statements as they are the best for checking the benefits of direct I/O.
>
> What metrics should I be focusing on to "quantify" direct i/o benefit in
> my environment?
Well, the answer that is always correct is: "that depends". My favorite metrics
in
the winter months is the number of calories per serving. Alternatively, you can
try with the BCHR. Allegedly, that is a good overall number which tells you how
well your system would be performing had it not been for those pesky solar
flares.
>
> What I don't want to do is switch to direct i/o and have performance
> decrease (i.e. temp TS space was de-buffered) or not understand what/why
> performance decreased...
In order to measure the performance impact of switching to direct I/O, it would
be a good thing to measure your performance, in the first place. Completely
illogical
thing to do would be to develop a metrics to test your performance, then run a
test
to create a baseline against which you are testing, then switch to direct I/O,
rerun
the test and compare the results against the baseline. Unfortunately, my ESP
powers
are usually weak before summer so I cannot read your mind and create a test
that
would reflect your business model. My telepathic abilities increase
exponentially
if I am plied with copious quantities of Long Island ice tea, but as that is
not the
case, I can not help you.
>
--
Mladen Gogala
http://www.mgogala.com
--
//www.freelists.org/webpage/oracle-l
Other related posts:
