RE: negative value for buffer cache hit ratio

From: K Gopalakrishnan <kaygopal_at_yahoo.com>
Date: Tue, 07 Aug 2001 13:58:38 -0700
Message-ID: <F001.003636C7.20010807140702@fatcity.com>

Hi,

Generally speaking.. HIT RATIOS does not give the true picture always. I have seen databases performing extremely good with 50% and bad databases with 99% hit ratio.

You should never decide the database performance based on hit ratio and 90% hit ratio does not mean that 90% of the data is ALWAYS read from the cache. It translates in to something like this..A block is read (consistent get) 9-10 times before written to disk..

You should check your system wide wait statistics for better tuning..

• Ramon Estevez <com.banilejas_at_codetel.net.do> wrote:
  > Hi,
  >
  > My misses is
  >
  > MISS_RATE
  > ---------
  > 0.68%
  >
  > Is that good or bad, Oracle 8.0.5 Standard Edition,
  > Windows 2000.
  >
  > Is there a 8.1.7 Standard Edition Version ?
  >
  > Ramon Estevez
  > com.banilejas_at_codetel.net.do
  >
  >
  

  ---

Have a nice day !!

---

Best Regards,
K Gopalakrishnan,
Bangalore, INDIA.

---

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Author: K Gopalakrishnan
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Received on Tue Aug 07 2001 - 15:58:38 CDT