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Cost in explain plan [message #612908] Sun, 27 April 2014 10:19 Go to next message
suhasdba
Messages: 141
Registered: April 2013
Location: INDIA
Senior Member
Hi,

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

Thanks,
Suhas
Re: Cost in explain plan [message #612910 is a reply to message #612908] Sun, 27 April 2014 10:52 Go to previous messageGo to next message
Michel Cadot
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Location: Nanterre, France, http://...
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Have a look at Database Performance Tuning Guide.

Re: Cost in explain plan [message #612994 is a reply to message #612910] Mon, 28 April 2014 11:48 Go to previous messageGo to next message
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
Re: Cost in explain plan [message #612995 is a reply to message #612994] Mon, 28 April 2014 11:57 Go to previous messageGo to next message
Michel Cadot
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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.

Re: Cost in explain plan [message #612999 is a reply to message #612995] Mon, 28 April 2014 12:53 Go to previous messageGo to next message
suhasdba
Messages: 141
Registered: April 2013
Location: INDIA
Senior Member
Thanks for your suggestions.
Re: Cost in explain plan [message #613009 is a reply to message #612999] Mon, 28 April 2014 16:04 Go to previous message
John Watson
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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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