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I ran the following scripts..
SELECT parameter, gets, Getmisses,
getmisses/(gets+getmisses)*100 "Miss Ratio",
(1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit Ratio"
FROM v$rowcache
WHERE gets+getmisses <>0
GROUP BY parameter, gets, getmisses;
and I got the following results...
Miss Ratio Hit Ratio
---------- ---------
20 80
1.25 98.75
19.13 80.87
.9925 99.01
24.99 75.01
1.058 98.94
.3995 99.6
8.012 91.99
23.08 76.92
26.32 73.68
17.49 82.51
33.33 66.67
.6425 99.36
.5745 99.43
3.448 96.55
.377 99.62
Can you explain what's going on with the results?....
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Refer this doc, before you start doing the things with tuning.
http://www.oradoc.com/ora816/server.816/a76992/toc.htm
Sam
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Hit is the number of times a statement is requested and it is found in the cache. A Miss is when it is requested and not found in the cache.
For Rowcache the most important hit ratios to consider are dcobjects and dcsysnoyms. The sum of misses to gets should be less than 15%.
Maybe this link will be of some help. Check it out.
http://www.ecst.csuchico.edu/~melody...tune_stats.htm
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That reference was a good one!
Sam
