[XSL-LIST Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

RE: XPath "//", speed, and Saxon

Subject: RE: XPath "//", speed, and Saxon
From: "Michael Kay" <mike@xxxxxxxxxxxx>
Date: Mon, 3 Nov 2008 12:51:58 -0000
RE:  XPath "//"
> This example from my tutorial about testing XSLT [1] shows 
> the result of profiling the same stylesheet and data in both 
> xsltproc and Saxon: the two XSLT processors agreed on which 
> were the two most time-intensive templates, but after that, 
> their results differed.

Profiling is useful, but it also has considerable limitations. The more
powerful the optimizer, the harder it is to relate what happens at run-time
to your original source code.

Hence the rhetorical question in the paper: "...but why is a simple <hr/> a
hotspot?" (Answer could be, for example, because it often fills a buffer in
the serializer causing the serializer to process the buffer contents)

Incidentally, one minor comment

>Only xsltproc provides a command-line switch for running the transformation
time multiple times 

Saxon has had such a switch for some time, though only recent releases have
documented it (-repeat:99).

I think there's another important (if obvious) point that's not made in the
paper: don't assume that your performance problem is in the XSLT code until
you've drilled down to that level. I did a bit of tuning for a client
recently where it turned out 80% of the cost was spent in some simple
user-written code to generate the XML input for the transformation.

Michael Kay

Current Thread


Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Buy Stylus Studio Now

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Don't miss another message! Subscribe to this list today.
First Name
Last Name
Subscribe in XML format
RSS 2.0
Atom 0.3
Site Map | Privacy Policy | Terms of Use | Trademarks
Free Stylus Studio XML Training:
W3C Member
Stylus Studio® and DataDirect XQuery ™are products from DataDirect Technologies, is a registered trademark of Progress Software Corporation, in the U.S. and other countries. © 2004-2013 All Rights Reserved.