Re: CBC Latch contention in 10g

It's CPU dependent. The older CPU's did not have an atomic CAS (compare and swap)
instruction. In some cases this left Oracle using exclusive latches, in others Oracle worked around the problem by using a latch to emulate CAS... the 'cas latch' - which was subsequently joined by the 'rm cas latch'. You'd have to have a 3 or 4 year old CPU for this to be a problem though.

Regards

Jonathan Lewis

http://www.jlcomp.demon.co.uk/faq/ind_faq.html The Co-operative Oracle Users' FAQ

http://www.jlcomp.demon.co.uk/seminar.html Optimising Oracle Seminar - schedule updated Sept 19th

• Original Message ----- From: "Cary Millsap" <cary.millsap_at_hotsos.com> To: "'Oracle-L (E-mail)'" <oracle-l_at_freelists.org> Sent: Tuesday, October 19, 2004 9:41 PM Subject: RE: CBC Latch contention in 10g

I believe Steve Adams once told me that the shareable latch feature is = not
implemented on HP-UX.

Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
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