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From dag.wan...@oracle.com (Dag H. Wanvik)
Subject Re: embedded derby small foot print
Date Mon, 18 Jul 2011 13:50:55 GMT
Paul French <paul.french@kirona.com> writes:

> We run derby 10.5.1 on J9 on WM6.1/6.5
>
> The derby web site claims a small foot print of 2.6MB ? How do I
> achieve this? What is the 2.6MB actually measuring, heap, non-heap,
> both ?
>
> Our application is hitting resource problems on WM, so we need to tune
> all parts of the app as much as possible. For derby the only setting
> we have played with is:
>
> Dderby.storage.pageCacheSize=50
>
> ...which helps, but derby still looks like it is using 7M. Any ideas?

The 2.6Mb is the size of the code bundle. How much memory you need at
run time depends on your application and settings, and your milage may
vary. Make sure explicitly close resources as you go.

You could try to limit the heap with "-Xmx<X>M" and see how far doown
you can squeeze it. The minimum value for derby.storage.pageCacheSize is
40.

Also, you could try to disable the prepared statement cache trading
speed for space: Setting derby.language.statementCacheSize to 0 disables
it (default is 100). 

Dag

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