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RE: high cpu on query

From: Kerber, Andrew W. <Andrew.Kerber_at_umb.com>
Date: Fri, 29 Jun 2007 13:11:39 -0500
Message-ID: <D40740337A3B524FA81DB598D2D7EBB3097A862E@x6009a.umb.corp.umb.com>


We never found the cause, but we have fixed similar problems in the past by rebuilding the indexes on the table (alter index owner.indexname rebuild online;)

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Joe Armstrong-Champ Sent: Friday, June 29, 2007 11:57 AM
To: ORACLE-L
Subject: high cpu on query

We upgraded to 10.2 a month ago and everything was running fine until 2 days ago when a query started running very slow in prod. It is selecting

data from a view using distinct and does an 'order by', too. It runs ok in a copy of the db which was refreshed just after the upgrade. The difference in the number of rows between the 2 databases isn't that much

but the execution plans are very different. The indexes are the same in both. I manually updated the stats for the affected tables in another copy which was refreshed yesterday but the plan didn't change. There is a high percentage of cpu involved in the long running query.

Questions:
- what can cause a difference in the execution plans besides the stats
and indexes?
- in general what can cause a query to use a lot of cpu?

Thanks.
Joe

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Received on Fri Jun 29 2007 - 13:11:39 CDT

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