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Cost in explain plan [message #612908]

Sun, 27 April 2014 10:19

suhasdba
Messages: 141
Registered: April 2013
Location: INDIA

Senior Member

Hi,

How the cost is evaluated in explain plan ? could you explain.

Thanks,
Suhas

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Re: Cost in explain plan [message #612910 is a reply to message #612908]

Sun, 27 April 2014 10:52

Michel Cadot
Messages: 68165
Registered: March 2007
Location: Nanterre, France, http://...

Senior Member
Account Moderator

Have a look at Database Performance Tuning Guide.

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Re: Cost in explain plan [message #612994 is a reply to message #612910]

Mon, 28 April 2014 11:48

suhasdba
Messages: 141
Registered: April 2013
Location: INDIA

Senior Member

Michel,

I couldnt find the answer to my question in the given link.Could you help me to get answer ?

Thanks,
Suhas

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Re: Cost in explain plan [message #612995 is a reply to message #612994]

Mon, 28 April 2014 11:57

Michel Cadot
Messages: 68165
Registered: March 2007
Location: Nanterre, France, http://...

Senior Member
Account Moderator

It is quite complex, Jonathan Lewis wrote 2 books on this, you can buy them.
The overview is given in section 13.4.1.3.3 Cost in the previous link.
What do you want to know EXACTLY? If you want to know the exact algorithms and formulas, buy J. Lewis latest book.

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Re: Cost in explain plan [message #612999 is a reply to message #612995]

Mon, 28 April 2014 12:53

suhasdba
Messages: 141
Registered: April 2013
Location: INDIA

Senior Member

Thanks for your suggestions.

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Re: Cost in explain plan [message #613009 is a reply to message #612999]

Mon, 28 April 2014 16:04

John Watson
Messages: 8702
Registered: January 2010
Location: Global Village

Senior Member

There is no simple definition of the cost as calculated by explain plan. I blogged about it here,
http://www.orafaq.com/node/2746
and learned from the responses (particularly that from rleishman).

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