Re: *Measuring sql performance (elapsed time and scalability) by number of logical reads

On 5/2/06, Cary Millsap <cary.millsap_at_hotsos.com> wrote:
> In the trace data context, those things listed below (hash value
> calculation, memory management, traversing hash chains, etc.) will show
> up as time in the c field. ...Not as time in a "wait" event.
>
> I don't think the categorization "service" vs. "wait" helps people's
> thinking very much.
> A better way to think of the time being spent from
> Oracle's perspective is "kernel code path" vs. "OS call code path".
> Roughly speaking, the c field on a dbcall maps to kernel code path
> execution, and the ela field on so-called "wait" lines maps to OS call
> code path execution.

I think that instrumenting oracle kernel code path is as useful as OS call code path instrumenting is.

> Notice that an OS call duration includes both waiting and service time.
> This is the reason I don't like to use the word "wait interface".
>
>
> Cary Millsap
> Hotsos Enterprises, Ltd.
> http://www.hotsos.com
> Nullius in verba
>
> Hotsos Symposium 2007 / March 4-8 / Dallas
> Visit www.hotsos.com for curriculum and schedule details...

Regards,
Dimitre

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