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what is mean by query optimization? and Explain plan?How we optimize the query?? [message #217374] Thu, 01 February 2007 22:43 Go to next message
victoryhendry
Messages: 95
Registered: January 2007
Location: Bangalore
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what is mean by query optimization? and Explain plan?How we optimize the query??
Re: what is mean by query optimization? and Explain plan?How we optimize the query?? [message #217378 is a reply to message #217374] Thu, 01 February 2007 23:13 Go to previous messageGo to next message
BlackSwan
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Registered: January 2009
Location: SoCal
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This is NOT an expert question which can be answered by reading the fine Concepts Manual found at http://tahiti.oracle.com
Re: what is mean by query optimization? and Explain plan?How we optimize the query?? [message #217430 is a reply to message #217374] Fri, 02 February 2007 02:54 Go to previous message
martijn
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Registered: December 2006
Location: Netherlands
Senior Member
victoryhendry wrote on Fri, 02 February 2007 05:43
what is mean by query optimization? and Explain plan?How we optimize the query??


Query optimization is the process of changing an sql-query so that it will perform better (faster execution/less computer resources/...)

If you suspect an query can/must be optimized you can use the explain plan to see how the query is split up in smaller parts by oracle to see what's is done to come up with a result.

How to optimize a query depends (among others) on what the explain plan is telling you. (change joins/use indexes/....)

But.....as allready is mentioned : you must be able to find all of this in the manuals, which are quite comprehensive.

Best regards,

Martijn Bos.
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