[xquery-talk] performance figures for xquery processors

[Makoto YUI]

"Michael Kay" <mhk at mhk.me.uk> wrote:

> > 
> > In my laptop, Saxon can't load 100M xml document.
> > it is because memory space (total 768M/free about 250M) is 
> > insufficient, but it is scaling topic. That was why I put 
> > the issue.
> 
> How much memory did you allocate to the Java VM? Usually -Xmx512M -Xms512M
> should be sufficient for a 100Mb document, though if the processing is
> non-trivial it would be better to allocate more.

tested with -Xmx256m, -Xmx384m, "without -Xmx"..

I don't remember whether tested with -Xmx512m, sorry.

# Of course, I know with more memory spaces it'll run.

> > Object creation is still heavy even in latest JVM 
> > and each Object has at least 8 bytes! memory footprint, 
> > this costs.
> 
> This is why Saxon doesn't represent nodes of the tree using objects. The
> memory used by the tinytree is about 20bytes per node plus 2 bytes per
> character of text and attribute content. Attribute-intensive documents may
> take more space because attribute values are held as String objects.

If so, array expansion (re-allocation) might have been cost 
in the last test, while I have no proof.

# Though it is from my experience..

Makoto

--
Nara Institute of Science and Technology (NAIST)
Makoto YUI <yuin405 AT gmail.com>
http://db-www.naist.jp/~makoto-y/proj/xbird/