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Re: XPath 1.5? (was RE: typing and markup)

• To: Eric van der Vlist <vdv@d...>
• Subject: Re: XPath 1.5? (was RE: typing and markup)
• From: Jeni Tennison <jeni@j...>
• Date: Tue, 7 May 2002 15:31:24 +0100
• Cc: xml-dev@l...
• In-reply-to: <3CD7A716.7080705@d...>
• Organization: Jeni Tennison Consulting Ltd
• References: <001901c1f5a1$88103d70$6501a8c0@pcukmka><1341299411755.20020507104751@j...> <3CD7A716.7080705@d...>
• Reply-to: Jeni Tennison <jeni@j...>

Hi Eric,

>> I'm guessing, but I think that when people express doubts and fears
>> about the impact of XML Schema on XPath they are more concerned
>> over:
>
> I'd like to add a 5th item:
>
>    - the impact on the performances for real time transformations.
>      Even when used without schema, won't the added complexity
>      have an impact on the memory and speed of the transformations?

I think that part of the promise of the static type checking in
XQuery/XPath 2.0 is that it enables processors to optimise
queries/expressions. So that should make them faster to run. But then,
as Mike's said on many an occasion there's a trade-off to be made
between the time it takes to analyse a document or a transformation,
and the time that analysis saves you through optimisation.

Unless you're doing something really complicated, the thing that takes
the most time in an XSLT transformation is the parsing (and
serialising) of documents. Parsing and validating against an XML
Schema will take longer than simply parsing, but that won't make an
impact if you don't use XML Schema anyway, or if you turn validation
off and use hard-coded knowledge about types within the stylesheet.

Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/

• References:
  • RE: XPath 1.5? (was RE: typing and markup)
    • From: "Michael Kay" <michael.h.kay@n...>
  • Re: XPath 1.5? (was RE: typing and markup)
    • From: Jeni Tennison <jeni@j...>
  • Re: XPath 1.5? (was RE: typing and markup)
    • From: Eric van der Vlist <vdv@d...>

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