| hint usage. [message #227455] |
Wed, 28 March 2007 05:21  |
shahnazurs
Messages: 240
Registered: June 2005
Location: India
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Senior Member |
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Hi.
When we need to use hint in query? please explain me with some example.
Thanks,
Shahnaz.
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| Re: hint usage. [message #228727 is a reply to message #227459] |
Tue, 03 April 2007 23:57  |
shahnazurs
Messages: 240
Registered: June 2005
Location: India
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Senior Member |
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Hi Michel,
Could you please list out what are the different hints available for the cost based optimizer and show with some example in which situation we use which hint?
Thanks,
Shahnaz.
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| Re: hint usage. [message #228971 is a reply to message #227455] |
Wed, 04 April 2007 14:01 |
nmacdannald
Messages: 460
Registered: July 2005
Location: Stockton, California - US...
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Senior Member |
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Update your statistics and Oracle will really do a great job of optimising a query.
Hints: once in a great while it helps to make Oracle use an index that it was not going to. Or to specify join or cartanze (sp?) joins.
Almost always Oracle's optimizer will do a great job with out hints. In fact, certain cases where indexes are built and then dropped it hinders performance.
Learn how to read the query plan before attempting to change the query. In some of the later versions you can develop a plan for a particular sql statement and then anytime Oracle sees that sql it uses the plan.
[Updated on: Wed, 04 April 2007 14:01] Report message to a moderator |
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