RE: Oracle 10g RAC
- From: "Crisler, Jon" <Jon.Crisler@xxxxxxx>
- To: <smishra_97@xxxxxxxxx>, "Martin Berger" <martin.a.berger@xxxxxxxxx>
- Date: Fri, 14 Aug 2009 17:48:14 -0400
Go back and look at basic system statistics- perhaps you are getting
into a swapping situation ?
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Sanjay Mishra
Sent: Friday, August 14, 2009 10:58 AM
To: Martin Berger
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: Oracle 10g RAC
Martin
It is only one Sql in the application where the performance is reported
as it might be used very frequently. Regarding SQL execution plan, I am
not seeing the difference in the Execution Plan. I had even flush the
Shared pool to see if that has any impact but plan remain same and query
start behaving very fast with buffer cache flush. Also the time is
random and you can say that after every hour, we can see the performance
is degraded. Currently a job is schedule last week to flush the
expensive flush buffer cache operation as otherwise it is affecting the
application user severely and after that there is no issue reported but
that is not good approach.
thanks for your time and comments
Sanjay
________________________________
From: Martin Berger <martin.a.berger@xxxxxxxxx>
To: smishra_97@xxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
Sent: Friday, August 14, 2009 12:29:29 AM
Subject: Re: Oracle 10g RAC
Sanjay,
is it only a dedicated sql or does all selects behave like this?
if you have ash/awr licesed, can you run a ash report for this period of
time? (if not, you can manually sample event and seq# from v$session of
the session, which runs the sql currently)
did the execution plan change?
can you pin the time, when execution switch from fast to slow, and can
you classify the overall situation on your instances at this point of
time?
Just some starting questions to reduce guesswork.
regards,
Martin
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Am 14.08.2009 um 03:56 schrieb Sanjay Mishra:
Hi
I had 3 Node RAC on Solaris and I am facing one scenario very frequently
where a select query start taking too much time in execution. It take
only few seconds but after some time it changed to few minutes. At this
time if I flush Buffer Cache on all Node, it come back to same few
seconds and then after some time, it changed back to same situation. Any
expert comments as what can be issue here. Oracle 10.2.0.3. This RAC
environment is running 3 Database sand the problem is only with one
Database and so it is not linked to interconnect which can give this
issue. Also Select is only bringing few records and not high number of
records
TIA
Sanjay
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