RE: Is this hardware issue?

  • From: "Sweetser, Joe" <JSweetser@xxxxxxxx>
  • To: "lambu999@xxxxxxxxx" <lambu999@xxxxxxxxx>, "Blanchard, William G" <William.Blanchard@xxxxxxxxxxxxx>
  • Date: Mon, 22 Aug 2011 19:52:54 +0000

Which then begs the question....what is the old h/w and s/w configuration 
(assuming the 10.2. AIX, Clarion is the new h/w & s/w)?

From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of Ram K
Sent: Monday, August 22, 2011 1:46 PM
To: Blanchard, William G
Cc: oracle-l
Subject: Re: Is this hardware issue?


I understand once the data is cached it can be retrieved quickly from the 
buffers. I am wondering why it would take 7/8 minutes to get some data from the 
IO layer. This behavior is NOT the case in the old hardware. It comes back much 
faster. The plans are same, once again.

On Mon, Aug 22, 2011 at 2:20 PM, Blanchard, William G 
<William.Blanchard@xxxxxxxxxxxxx<mailto:William.Blanchard@xxxxxxxxxxxxx>> wrote:
This is expected behavior.  The first time you run the query, it has to read 
everything into the buffer cache (db file sequential read).  Every time after 
that (especially since nobody else is using the database) the information for 
the query is already cached and can be read right from the cache.


WGB


From: oracle-l-bounce@xxxxxxxxxxxxx<mailto:oracle-l-bounce@xxxxxxxxxxxxx> 
[mailto:oracle-l-bounce@xxxxxxxxxxxxx<mailto:oracle-l-bounce@xxxxxxxxxxxxx>] On 
Behalf Of Ram K
Sent: Monday, August 22, 2011 2:14 PM
To: oracle-l
Subject: Is this hardware issue?

List,

We are moving our stuff from old hardware to a new hardware. I am observing 
these results in our new test hardware env: we run a query in the new test env, 
it runs slow first time it is run. It takes about 6/8 minutes. Once the query 
is run once, if it is ran again, it comes with results in matter of seconds. 
This happens a few times and then I flush the buffer cache or bounce the DB and 
rerun the query, the response time goes back to 7/8 minutes and the subsequent 
responses are in matter of seconds. I was able to repeat this behavior a few 
days. I ran the 10046 and checked the plans. The plans in both cases are same. 
The increased wait seemed to come from waiting longer for the same "db file 
sequential read" event. Could this point to hardware issues, like I/O or VIO?

No other user is using the database when I do this test, v10.2. OS is AIX, 
disks on Clarion SAN. Although there are couple of other databases running in 
this test server, there is no load from them in terms of CPU or memory. I 
tested in during normal hours, after hours when no one uses any of the DBs in 
the server. The results are consistent.

--
Thanks,
Ram.

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--
Thanks,
Ram.
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