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From Thomas Nielsen <Thomas.Niel...@Sun.COM>
Subject Re: Optimizer question
Date Fri, 07 Dec 2007 19:36:36 GMT
Army wrote:
> Oops, sorry about that.  I was just reading your email, I didn't read 
> the comments on DERBY-2998.  Apologies for the noise...

I wasn't expecting you to either - apologies if I sounded like that. And 
it's by no means noise to me - it was acutally truly rewarding to see 
that my interpretation was correct! :)

>> One of the results of adding the extra if 
>> (!ref.pointsToOLAPFunction()) was that certain very simple joins 
>> started failing.
> Simple joins involving ROW_NUMBER(), or simple joins having nothing to 
> do with OLAP? (just curious)

A simple join with a row_number() produces the wrong results:

   select row_number(),x from t2,t3 where x=y

>> I should probably reenable the push, and start tracking down why the 
>> join fails.
> I think that's a good next step.  If it turns out that this approach 
> is not going to work, it would at least be good to understand more 
> about why--and maybe that'll provide pointers to an alternate 
> approach, if needed...
Ok - I'll head down that path

Again - thanks Army. You made my day!

Thomas

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