- From: <bugzilla@wiggum.w3.org>
- Date: Wed, 15 Apr 2009 15:57:23 +0000
- To: www-xml-schema-comments@w3.org
http://www.w3.org/Bugs/Public/show_bug.cgi?id=5023 --- Comment #13 from Erik Wilde <dret@berkeley.edu> 2009-04-15 15:57:23 --- i think assumptions about optimizations built into processors are a bit optimistic. for example, a very obvious optimization in the space of XML implementations would be to use xsl:key for building an index, but recently i ran into an XSLT processor (in a highly successful commercial product, XML Spy), which does not seem to do so. i am not sure, but the performance really looked as if they treated every key() call as a search of the document tree. http://dret.typepad.com/dretblog/2008/12/itunes-xml.html more generally speaking, this is the spectrum of limited declarative vs. more expressive procedural languages, and XPath 2.0 has opened the door quite a bit to make XPath so expressive that is has become much harder to optimize. my guess is that most XSD implementers will not bother to carefully optimize XPath expressions (are there already test cases for XSD 1.1? do they contain sophisticated XPath assertions? do they maybe even contain functionally equivalent XSDs that use different constraint mechanisms to do the same thing? that might be a worthwhile set of additions to the test cases.), also because they might simply use existing XPath 2.0 libraries instead of implementing XPath 2.0 as a part of their XSD 1.1 implementation. -- Configure bugmail: http://www.w3.org/Bugs/Public/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the QA contact for the bug.
Received on Wednesday, 15 April 2009 15:57:32 UTC