[Topaz-dev] [Topaz-pubapp-dev] Mulgara Performance Woes

[Andrae Muys]

On 05/03/2008, at 8:24 AM, Life is hard, and then you die wrote:
> On Tue, Mar 04, 2008 at 10:47:41AM -0800, Russell Uman wrote:
>> i also notice that no -Xmx parameter is set for mulgara in
>> /etc/sysconfig/mulgara - i think the theory was that mulgara wouldn't
>> need a lot of memory and we'd want to leave as much RAM open for
>> OS-level file caching as possible - does everyone still feel the same
>> way?
>
> The RAM is needed for mmap'ing the db files. Mulgara is not using much
> memory at all and is nowhere near the current max. Run visualgc (in
> ~topazdev/jvmstat/bin/visualgc) to see a pretty picture of things.
>
> So no, don't change that parameter (I suppose you could lower it a
> bit).

That being said, there are a couple of circumstances where Mulgara  
does do some caching in the heap, but they are associated with large  
intermediate query results, and clearly don't apply here.

Andrae

-- 
Andrae Muys
andrae at netymon.com
Senior RDF/SemanticWeb Consultant
Netymon Pty Ltd