Re: V$LATCH question

I don't think you are correcting me at all. I think you are just restating and expanding on the points I had made that the second option is (a) unlikely, and (b) a secondary symptom of something much more basic.

If you have ever been on a site where a dba took the advice

    "you can reduce latch sleeps
    by increasing the _spin_count"
a little too enthusiastically, you would realise that it is possible for a spin value of 50,000 does not result in a trivial amount of CPU loss.

On a more serious note - you mentioned that sleeps are for 10 milliseconds - but all the measurements I make on HP suggest that
the sleep time on the cache buffers chains latch is 20 milliseconds. Is this something that may vary with platform ?

--
Jonathan Lewis
http://www.jlcomp.demon.co.uk

Host to The Co-Operative Oracle Users' FAQ
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Author of:
Practical Oracle 8i: Building Efficient Databases

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Use spare CPU to assist in cancer research.

Ricky Sanchez wrote in message <3C08F1E5.6E4FBEC6_at_more.net>...


>A slight correction...

>




>Jonathan Lewis wrote:




>

>Once you have addressed the hardware issues, perhaps by replacing slow

>CPUs with faster hardware, you are likely to find that the dynamics of

>the instance have changed altogether. You may no longer have a latch

>problem.

>

>Put another way, if performance is a problem, as witnessed by high

>"latch free" waits, pay attention to the "sleepiest" latch and ignore

>misses and spin-gets altogether.

>