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RE: eXelon performance

On Tue, 11 Apr 2000, David Duddleston wrote:
> Falko, thanks for doing the test and reporting the detials on the process.
> 20K method calls is allot. Any idea on the number of objects created? I
> agree, some sort of alternative method is needed to speed performance. I
> can't imagine how long it would have taken to do the query accoss all 8megs
> of files.

Xalan needs approx. 1.8s x 30 = 54s (for all 30 files) to process the query on
in-memory DOM! This is five times slower then eXcelon on the database! This is
without the overhead of ozone......


Falko

> 
> -david
> 
> 
> > -----Original Message-----
> > From: Falko Braeutigam [mailto:falko@softwarebuero.de]
> > Sent: Tuesday, April 11, 2000 11:48 AM
> > To: ozone-users@ozone-db.org
> > Subject: 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
> > --
> > ______________________________________________________________________
> > Falko Braeutigam                         mailto:falko@softwarebuero.de
> > softwarebuero m&b (SMB)                    http://www.softwarebuero.de
> >
-- 
______________________________________________________________________
Falko Braeutigam                         mailto:falko@softwarebuero.de
softwarebuero m&b (SMB)                    http://www.softwarebuero.de