[XML-SIG] Re: [4suite] Great Reason for 4Suite Release delay

[Uche Ogbuji]

Damien Morton wrote:
> 
> Wow! Congratulations on such an amazing speedup.
> 
> Id love to hear a summary of the kinds of things done to achieve this
> speedup.

An honest statement of what we've done is kill the lion's share of
performance *bugs*.  This mostly involved redundant loops and tree
descents in XPath, with some clean-up of the interface between XPath and
XSLT.

The only design optimization we put in was to develop a micro-dom for
XPath that we call "Domlette".  This is a scaled-back, read-only DOM
subset specialized for XPath (along the spirit if not implementation of
Xalan's DTM).  This was perhaps a fifth of the performance gains we had,
with most of the other gains coming from fixing performance bugs.

We still haven't done many of the performance design improvements we're
planning such as better indexing and expression optimization.  These
will mostly benefit documents in the megabytes.

-- 
Uche Ogbuji                               Principal Consultant
uche.ogbuji@fourthought.com               +1 303 583 9900 x 101
Fourthought, Inc.                         http://Fourthought.com 
4735 East Walnut St, Ste. C, Boulder, CO 80301-2537, USA
Software-engineering, knowledge-management, XML, CORBA, Linux, Python