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From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: [jira] Commented: (DERBY-2130) Optimizer performance slowdown from 10.1 to 10.2
Date Thu, 30 Nov 2006 22:49:43 GMT
just so we are working on the same case, when you run is there
also 0 rows in all the tables?

Bryan Pendleton wrote:
>  >  * I did not see the non-deterministic behavior that Bryan did
>  > with 10.2 trunk--instead, I consistently see 7+ minutes.  However,
>  > I only ran the query 3 times, which is probably not enough to have
>  > seen what Bryan saw.  Also note that I only ran the DDL one time
>  > and then I re-ran the query the second two times.  So given Mike's
>  > previous comment, this may be the reason I didn't see the variance 
> that Bryan did.
> 
> Thanks for all the help and good suggestions so far -- they have given
> me a lot of ideas to pursue.
> 
> I think that Mike's theory about the source of the non-determinism
> being due to whether I recreate the tables each time, or re-use the
> existing tables, is a good one, and I'll see if I can confirm it
> with more tests of my own.
> 
> Meanwhile, I'll also investigate the other pointers you passed along.
> 
> Regarding the comment that the DERBY-2130 test case is a hairy one,
> and it would be easier to start with a simpler one, I agree. On the
> other hand, the appeal of the DERBY-2130 test case is that:
> a) it is complicated enough to vividly show that there is a problem
> b) it is still pruned down enough so that it runs; some of my other
> test cases ran for hours and "never" terminated :)
> 
> Again, thanks for all the help and ideas; they are much appreciated.
> 
> bryan
> 
> 
> 
> 


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