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From Bernd Fondermann <bf_...@brainlounge.de>
Subject Re: Problems using Derby for stores
Date Sat, 12 Nov 2005 21:50:25 GMT
Daniel, thank you for pointing this out.
However, 64M was only used to trigger OutOfMemorys sooner in the first 
place. A more realistic load szenario should probably have much bigger 
heap, so I increased Xmx to 500M. After 12hrs still no shortage in memory...


-- Bernd

Daniel John Debrunner wrote:

> 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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