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Re: CBC Latch contention in 10g

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Thu, 21 Oct 2004 14:00:51 +0100
Message-ID: <003101c4b76d$fddddb30$6702a8c0@Primary>

    

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

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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Received on Thu Oct 21 2004 - 07:57:18 CDT

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