Oracle Database Administration Blog » Database optimization http://www.bestremotedba.com Specially Created for Remote DBAs and Junior DBAs Fri, 30 Dec 2011 05:43:39 +0000 en hourly 1 http://wordpress.org/?v=3.2.1 How to Calculate Hit Ratio from Tkprof output http://www.bestremotedba.com/how-to-calculate-hit-ratio-from-tkprof-output/ http://www.bestremotedba.com/how-to-calculate-hit-ratio-from-tkprof-output/#comments Wed, 23 Sep 2009 00:05:20 +0000 mudhalvan http://www.bestremotedba.com/?p=74

 Tkprof will have three fields in output
1. Disk
2. Query
3. Current
Generally hit ratio is calculated like as follows
 Hit Ratio = 1 – (Physical Reads/Logical Reads)

Physical Reads = Sum (Disk)
Logical Reads  = Sum (Query) + Sum (Current)

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