Craig Shallahamer's Blog
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You were brought to this page based on an internet search
and as a free service to Oracle DBAs.
The text below is an except from the book,
Oracle Performance Firefighting, written by
Craig Shallahamer of
OraPub, Inc.
Figures and tables are not included on this page, only their reference.
To order the book in either print or PDF form, click
here.
©2009, 2010 by Craig Shallahamer. This is copyrighted material.
Please—Out of respect for those involved in the creation of the book and also for
their familes, we ask you to respect the copyright both in intent and deed. Thank you.
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<p>1 If you are a queuing theory wiz, based upon the number of CPU cores, the utilization, and the run queue, you can mathematically predict how much time the Oracle processes sat in the run queue and how much time they were actually being served by a CPU core. Cool stuff, but the not the focus on this chapter. If this seems interesting to you, considering reading my book Forecasting Oracle Performance (Apress, 2007).
</p><p>2 In fact, based on my extensive data collection tool experience, Oracle does not always collect and report background CPU consumption through the v$sysstat or v$sesstat views. While this can present a problem when gathering detailed data used during predictive analysis, for firefighting performance analysis, the background CPU time is not likely to be significant enough to cause a misdiagnosis.
</p><p>3 Some of you reading this may feel I'm getting uncomfortably close to performance ratio analysis. I understand your concern, but considering the resulting ratios are only one small part of a solid ORTA, a complete 3-circle analysis, and no action will be taken unless your ORTA directs it, I'm not concerned, and I hope you're not either. Don't, as they say, throw the baby out with the bathwater. Percentages are a fantastic way for us to relate raw numerics from one situation to another. Don't let any disdain for ratio analysis cloud their usefulness when properly used.
</p>
©2009, 2010 by Craig Shallahamer. This is copyrighted material.
Please—Out of respect for those involved in the creation of the book and also for
their familes, we ask you to respect the copyright both in intent and deed. Thank you.
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