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Query fetching time before hand [message #448761]

Thu, 25 March 2010 02:26

orafacjublu
Messages: 95
Registered: May 2006
Location: KOLKATA

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Can we predict the query fetching time of all the rows before hand without executing the query. If so please share.

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Re: Query fetching time before hand [message #448772 is a reply to message #448761]

Thu, 25 March 2010 02:38

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

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We can't but the optimizer can estimate it (and does it).

Regards
Michel

[Updated on: Thu, 25 March 2010 02:39]

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Re: Query fetching time before hand [message #449223 is a reply to message #448761]

Sun, 28 March 2010 06:14

Kevin Meade
Messages: 2103
Registered: December 1999
Location: Connecticut USA

Senior Member

Oracle has the capability. Bit it does not expose these particular internals with an API yet, so we can't get at it.

Maybe in some future release...

I am curious, why do you want to know? What were you planning on doing with the information?

Kevin

[Updated on: Sun, 28 March 2010 06:15]

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Re: Query fetching time before hand [message #449234 is a reply to message #449223]

Sun, 28 March 2010 08:17

Michel Cadot
Messages: 68650
Registered: March 2007
Location: Nanterre, France, http://...

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Well, we can do the same thing than the optimizer (maybe not so cleverly than it) using the statistics.

Have a look at MOS Note "Predicate Selectivity" [ID 68992.1]

Regards
Michel

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