Re: high db hit ratio and a lot of waits on db sequential reads

From: fmhabash <fmhabash_at_gmail.com>
Date: Wed, 26 Sep 2007 12:12:20 -0400
Message-ID: <46FA84E4.2000601@gmail.com>

For my edification, can you please provide these metrics ...
- LIO/sec

• PIO/sec
• if you look at your sql ordered by PIO, what do you see there. Can you tell from the code what tables are being read from disk and why?

Also, on a finely tuned DB and in the absence of any other significant wait events (e.g. log sync, scattered ...., etc), why wouldn't you expect to see DBFSR as the top one. After all ,that's what the DB should be doing serving user requests. The question, then, becomes how costly it is. If you are doing less than 20ms, then you have no reason to loose sleep over it (not that you are).

Thank you

Fred Habash, Lead Oracle DBA (OCP 8i,9i) Oracle Team Portal http://spc-00sv0d03e3.spc.supc.com/ddcports/oracle/

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ACS HealthCare Solutions Dearborn, MI | Off.: 248-226-8778 | fhabash@acs-hcs.com | http://www.acs-hcs.com

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Received on Wed Sep 26 2007 - 11:12:20 CDT