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Query fetching time before hand [message #448761] Thu, 25 March 2010 02:26 Go to next message
orafacjublu
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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.
Re: Query fetching time before hand [message #448772 is a reply to message #448761] Thu, 25 March 2010 02:38 Go to previous messageGo to next message
Michel Cadot
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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 Go to previous messageGo to next message
Kevin Meade
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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 Go to previous message
Michel Cadot
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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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