RE: Important: Oracle processes taking lots of CPU

Hi New DBA,

>As I understand, the CPU is used while performing
>LIOs, doing calculation, sorts or while spinning for
>the latches. My understanding might be wrong! Since
>there aren't enough LIOs or complex calculations
>involved I thought that spinning for latches might be
>causing excessive CPU.

Spinning does cause CPU issues. I believe that if you have many processes and comparatively lesser number of processors, then you might have a lot of CPU consumption that is unaccounted for as cycles used for process context switching is not accounted in oracle. You will have to then look at 'sar -u' ( look for high %sys), 'sar -q' (look for high run queue size and occupancy) and 'sar -w' (look for excessive process switches).

Let us know if this helps,
John Kanagaraj <><
DB Soft Inc
Phone: 408-970-7002 (W)

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