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From Kathey Marsden <kmarsdende...@sbcglobal.net>
Subject Re: Advice in debugging plan selection
Date Wed, 18 Jun 2008 17:28:25 GMT
Bryan Pendleton wrote:
> Does it sometimes return 4, and sometimes return 9, all on the same 
> machine?
Yes sometimes 4, 5,9 and as high as 12 on the same linux 32bit box.  If 
I just run this code standalone, (outside of Derby) I consistently get 
5.  One thing I wonder about is if there might be other threads 
allocating objects at the time this  is running, which would throw 
things off.  Maybe this class should get loaded at boot time, so we can 
be sure nothing else is going on.

 Also I think I might try to gc() before the measurements and see if 
that makes a difference, but it seems to me that would only make the 
value larger.

Army mentioned to me that we might be able to use Map.Entry for this 
calculation more effectively, so I am looking at that too, but don't 
quite understand how that would work.

> I don't think this is likely to be a JVM bug. I think it's more likely
> that this code just isn't very robust.

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