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From "Laura Stewart" <scotsmat...@gmail.com>
Subject Re: optimizer documentation
Date Mon, 12 Jun 2006 18:40:32 GMT
*** (LS) Sorry, accidently sent before I finished my list of questions :-)
See below.

On 6/12/06, Laura Stewart <scotsmatrix@gmail.com> wrote:

>  *** (LS) Rick - I can work on updating this text... questions below.
>
>  On 6/12/06, Satheesh Bandaram <bandaram@gmail.com> wrote:
>
> > Rick Hillegas wrote:
>
> > "If memory use is not a problem for your environment, set this
> > property to a high number; allowing the optimizer the maximum
> > flexibility in considering a join strategy queries involving large
> > queries leads to better performance. It can also be set to smaller
> > values for more limited environments."
> >
> > I can't find the name of this property on that page of the Tuning
> > Guide. I'm also confused about what we consider to be a "high number"
> > versus what we consider to be "smaller values". Would appreciate
> > advice here.
>
> The property it may be referring to is
> *derby.language.maxMemoryPerTable*. The default value is 1024 KB.
>
> Current default value is too small, so it would be a good tip for
> developers to know and tune this property. It would be great if Derby
> can configure this property value based on factors like max heap size,
> size of data cache and/or other parameters.
>
> If you are opening a documentation bug for other issue you found, may be
> you can include this omission as well.
>
> Satheesh
>
> *** (LS) Questions
>
- Are we sure that the name of the property is
derby.language.maxMemoryPerTable ?
-  What is the maximum value allowed?
- Is there a value that we want to recommend for users to specify?
- The text says that it can be set to smaller values, what is the minimum
value that we recommend?

Laura Stewart

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