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Tuning option selection (merged 2) [message #511071]

Thu, 09 June 2011 07:12

a_oracle
Messages: 98
Registered: November 2010

Member

Hi,
New to tuning terminologies so need your expertise.
Just a general question :--
I have a query which I tuned using two methods:
Method 1: executed query in milliseconds,say 219 milliseconds but the cost is more.
Method 2: executed the query taking slightly more time(say,600 milliseconds) than method 1 but the cost is less.

Now, seeing the performance currently of the tuned query, I can apply any, but need your advice as which method is the best. Should we consider selecting the tuned query which takes minimal cost or the other one.

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Re: Tuning option selection (merged 2) [message #511073 is a reply to message #511071]

Thu, 09 June 2011 07:28

cookiemonster
Messages: 13972
Registered: September 2008
Location: Rainy Manchester

Senior Member

Never read too much into cost - it's an approximation of how much work oracle thinks it's going to take and depends on lots of factors.
I'd be more interested in the time. However your times are probably within margin of error.
So get more data in the tables so it takes longer and compare again.

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Re: Tuning option selection (merged 2) [message #511664 is a reply to message #511071]

Tue, 14 June 2011 08:17

michael_bialik
Messages: 621
Registered: July 2006

Senior Member

Compare also the number of buffer gets and disk reads performed by each statement.

HTH.

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