RE: high cpu on query

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@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] 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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