RE: Going to Cost

From: Miller, Jay <JayMiller_at_TDWaterhouse.com>
Date: Mon, 28 Jan 2002 08:34:02 -0800
Message-ID: <F001.003FD570.20020128083414@fatcity.com>

A few questions and suggestions:

What version of Oracle are you running?
Identify the SQL that is run most frequently and compare the explain plans under RULE and CHOOSE
Do the same with any reports. These are most likely to suddenly do ridiculous sort/merge joins killing performance.
Did you analyze all your tables *except* those owned by SYS (analyzing SYS owned tables will give very poor performance)

This is actually a great opportunity for you. I learned a huge amount about reading Explain Plans and tuning SQL when we made our switch.

Jay Miller
x48355

-----Original Message-----
Sent: Tuesday, January 22, 2002 12:06 PM To: Multiple recipients of list ORACLE-L

I have a large app that is still running rule based, we are finally going to take the plunge and try to start going cost based. The first time we tried this the performance was terrible in a lot of places. Does anyone have any good white papers or hints/tips on what to look for on areas that might be problems or pitfalls?
tia
... --- ... .... . .-.. .--. -- . .. .----. -... . . -. .--. .-. --- -... .-..

John B. Shaw        
           (ribit)
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       o  o       
       ( -- )

/\( , ,)/\
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Received on Mon Jan 28 2002 - 10:34:02 CST