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From Kurt Huwig <k.hu...@iku-ag.de>
Subject Derby speedup by not using page caches?
Date Sun, 01 Mar 2009 01:00:45 GMT
Hi,

I just stumbled upon this page

http://varnish.projects.linpro.no/wiki/ArchitectNotes

where the author writes that caching of disk files within the application hurts 
performance on current operating systems. Right now, the data is in memory at 
least twice: the OS cache and the Derby cache which sounds suboptimal. And it 
gets worse if the OS decides to swap out the application's cache.

With the widespread use of 64-bit machines and therefore a huge address space, 
is it possible to (optionally) disable the page cache and use memory mapped 
files instead? This would also solve the "how much page cache to use?"-problem. 
Sure on 32 bit you are limited to a database size of 1-3 GB but you should 
still see the speedup, especially on low memory systems.
-- 
Kurt
GnuPG 1024D/99DD9468 64B1 0C5B 82BC E16E 8940  EB6D 4C32 F908 99DD 9468

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