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Home -> Community -> Mailing Lists -> Oracle-L -> Re: cache buffer chains contention
It's certainly possible for Oracle to be pushed into very heavy CPU usage, particularly for PX slaves, but even in serial queries.
Two common 'causes' are queries with
correlated sub-queries against small tables;
and queries which have been over-indexed
and hinted to avoid table-scans.
Bottom line, though, is that if the session does not appear to be in an Oracle-recorded wait state, it is either using (or scheduled to use) CPU, or you've hit a wait state that isn't instrumented properly.
Jonathan Lewis
http://www.jlcomp.demon.co.uk
Host to The Co-Operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html
Author of:
Practical Oracle 8i: Building Efficient Databases
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Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Jonathan Lewis
INET: jonathan_at_jlcomp.demon.co.uk
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