RE: Buffer Hit Ratio

Hi Leonardo,

Have a look at the tip on "Calculating the Cache Hit and Miss Rates" on the Ixora web site at http://www.ixora.com.au/tips/tuning/cache_miss.htm.

@ Regards,
@ Steve Adams
@ http://www.ixora.com.au/
@ http://www.christianity.net.au/

-----Original Message-----
From: Leonardo Fernandez [mailto:lfernand_at_cmsenergy.com] Sent: Saturday, 21 October 2000 7:35
To: Multiple recipients of list ORACLE-L Subject: Buffer Hit Ratio

Hi All,
What is the best SQL to determine Buffer Cache Hit Ratio?

I have the following scritps(orasnap), but I'm not convinced, because there are several scritps?

select   sum(decode(NAME, 'consistent gets',VALUE, 0)) "consistent gets",
         sum(decode(NAME, 'db block gets',VALUE, 0))   "db block gets",
         sum(decode(NAME, 'physical reads',VALUE, 0))  "physical reads",
         round((sum(decode(name, 'consistent gets',value, 0)) +
            sum(decode(name, 'db block gets',value, 0)) -
            sum(decode(name, 'physical reads',value, 0))) /
         (sum(decode(name, 'consistent gets',value, 0)) +
         sum(decode(name, 'db block gets',value, 0))) * 100,2) "Hit Ratio"
from     sys.v_$sysstat

Please correct me if I am wrong. Thanks for your opinion ...

Regards,
Leonardo Fernández

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Please see the official ORACLE-L FAQ: http://www.orafaq.com
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Author: Leonardo Fernandez
  INET: lfernand_at_cmsenergy.com

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