Re: Oracle slowed down

On Fri, 21 Apr 2006 02:33:53 +0000, Bob Jones wrote:

>
> May I aslo suggest reading Oracle's official performance tuning books?

In which they discuss the ratios as an indicator of buffer cache size issues - to be used when statement, application, I/O and system tuning have been completed. Unfortunately many people skip over the 'yes but' part.

Bottom line - BCHR calcs can be caused to show just about any value one wishes. There are a number of sites and books (as indicated) that show how you can generate virtually any BCHR without changing anything in the system.

A good BCHR may be the result of very, very poorly written tablescanner. So the novice DBA and developer feel great that they have achieved the best possible performance for a piece of crappy code. Similar to putting in wait loops into C and tuning the heck out of the call stack.

-- 
Hans Forbrich                           
Canada-wide Oracle training and consulting
mailto: Fuzzy.GreyBeard_at_gmail.com   
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