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From Daniel John Debrunner <...@debrunners.com>
Subject Re: Problems using Derby for stores
Date Wed, 09 Nov 2005 12:08:19 GMT
Bernd Fondermann wrote:

> I set up a local test environment and eventually saw
> (a) OutOfMemorys (but only after a longer period of time, with -Xmx64M)

It may be that the Derby page cache is too big for this memory size. By
default the page cache is 1000 pages, and the default page size is 4k.
However I would guess with James that the default page size is 32k, as
it increases for tables with BLOBs/CLOBs or long rows. Thus the page
cache is much bigger when using BLOBs etc.

You can try bumping the page cache size down,

derby.storage.pageCacheSize=100

http://db.apache.org/derby/docs/10.1/tuning/rtunproper81359.html

Either as a system property, or in the derby.properties file.

This is a know issue in Derby, I think there are a couple of possible
solutions:

 1) define memory usage in Mb, not pages

 2) better dynamic configuration when OutOfMemory exceptions are seen,
    e.g. dynamically reduce cache.

Dan.



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