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RE: eXelon performance

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?

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