RE: Is this hardware issue?
- From: "Blanchard, William G" <William.Blanchard@xxxxxxxxxxxxx>
- To: <lambu999@xxxxxxxxx>, "oracle-l" <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 22 Aug 2011 14:20:03 -0500
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] 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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