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Jonathan Lewis wrote:
> "Frank van Bortel" <frank.van.bortel_at_gmail.com> wrote in message
> news:dntuku$bke$1_at_news5.zwoll1.ov.home.nl...
>
>>Dexter wrote: >> >>>When i run a query with a parallel hint say /*+ parallel (a,8) */ , it >>>doesnot seem to get any parallel slaves, though all parallel servers >>>are idle. >>> >>>When i check the run-time plan, it appears to have chosen parallel but >>>there are no parallel slaves. >> >>And an hint is an hint, not a directive. >>- are table(s) involved parallel? >>- are statistics up to date? >>- how did you come to the conclusion, no slaves >> were being used? >>- how did you generate the plan? >>
We do actually agree here, but it's the choice of words: http://asktom.oracle.com/pls/ask/f?p=4950:8:11506770631431808713::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:8912905298920
<quote>
A hint "should be taken", if it is possible and sensible to take it </quote>
So: a hint cannot be a directive (as you do acknowledge), as it can
be out of context.
Maybe I take the word directive too strong? Army green and blue
pop to my mind with that word. And I do acknowledge the
fact hints cannot (should not) be ignored at whim by the
optimizer.
As to your example: the question about indexes being used either parallel or not, was on my list, but as the OP stated "explain showed parallel execution was used, but no parallel slaves were seen", I took it of again.
-- Regards, Frank van Bortel Top-posting is one way to shut me up...Received on Fri Dec 16 2005 - 07:10:37 CST