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RE: eXelon performance

On Tue, 11 Apr 2000, Falko Braeutigam wrote:
> On Mon, 10 Apr 2000, David Duddleston wrote:
> > > Thanks for the info, David. I will check this with ozone and post
> > > results here.
> > > Maybe this is good starting point for a server independent XPath
> > > benchmark. Or
> > > does such a thing already exist?
> > 
> > I don't think anything like this exists, since it is so new. There are only
> > just a few XML storage solutions that support Xpath. I'll be very interested
> > in your results Falko. I'm going to run the same test with Xalan in the next
> > few days just for the heck of it. Let me know if there are any other tests
> > you would like me to run with eXelon.
> 
> [tests on a 400MHz, 64MB Linux/Intel box jdk1.2rc1]
> 
> ozone uses Xalan. So an ozone XPath query is only as fast as the Xalan
> implementation. To process the first of your example queries on a_and_c.xml
> Xalan needs 200000 method calls !!! In memory this takes 1.8s. (!) In the
> database this takes 11s. If we take into account what ozone needs to do on each
> method call (checking access right, object activation, transaction isolation,
> aquiring locks) the ratio is good. However, the overall performance compared to
> eXcelon is bad.
> 
> These test results reflect the disadvantages of the current ozone/XML
> architecture. We are using Xalan, which is not aware that it runs on a
> *persistent* DOM and therefore does no optimizations in this regard. And we are
> using a persistent DOM that is a simple port of a non-persistent DOM, again
> without optimizations. --> less development work - low performance. The first
> way I see to increase performance is to rework the DOM implementation
> regarding the needs of ozone. Any ideas?

David and all, here are some news from the XML XPath performance front.

With Xt instead of Xalan and the new directly-invoke-in-VM-call-proxies
ozoneXML needs 0.4s for the above XPath query! (warm database cache) This is
much more comparable to the eXelon performance reported by David (around 0.3s;
probably warm but I'm not sure) than the 11s reported for ozoneXML/Xalan.

Seems that we are on the right track here :)


Falko
-- 
______________________________________________________________________
Falko Braeutigam                         mailto:falko@softwarebuero.de
softwarebuero m&b (SMB)                    http://www.softwarebuero.de