RE: Reading statspack reports

  • From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxxxxx>
  • To: <cemail_219@xxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Wed, 1 Mar 2006 13:21:24 -0500

http://www.oraperf.com/ does a pretty good analysis of StatsPack
reports.  It's probably worth a look.

I always start with a quick check of Execute to Parse % and % Non-parse
CPU in the instance efficiency percentages.  After that it's on to the
Top 5 Timed Events.  From there, it really depends on what events appear
in the Top 5.

CPU time?  Look at your SQL ordered by Gets.....any SQLs doing insane
numbers of buffer gets/exec?
db file sequential read?  Again, look at SQL ordered by Gets, and
possibly also SQL ordered by Reads.
db file scattered read?  Again, poorly tuned sql....
enqueues?  Needs more analysis...could be application design issues,
could be block level concurrency, could be several different things, you
need to deep dive into the enqueues data and see which specific enqueues
have the most waits.
log file sync?  Look at commit frequency and also response time of the
disks the online redo logs are on
latch free?  Depends on the latch.  Cache buffers chains is likely to be
either inefficient SQL, or possibly some Oracle bug

This is a *far* from complete list....The idea is, start with the Top 5
Timed Events, cause that's where the bottlenecks are.  Depending on what
YOUR Top 5 are, will tell you where to go next.

Hope that helps,

-Mark



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Mark J. Bobak
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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of J. Dex
Sent: Wednesday, March 01, 2006 12:14 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Reading statspack reports

Does anyone have a quick cheat sheet for reading statspack reports or
can 
refer me to a site where I can obtain it?   I've seen a lot of stuff on 
Metalink but nothing that is short of quick and to the point.

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