Re: XSL: For-Each Efficient or Not?

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Subject: Re: XSL: For-Each Efficient or Not?
From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>
Date: Mon, 01 Jul 2002 11:44:48 -0400

disable output escaping performance impact

What Kevin says about the performance impact of complex matches would also seem to provide another reason why an XPath like

m:apply[factorof[not(preceding-sibling::*)]]

will be better than

m:apply[child::*[position()=1 and name()='factorof']]

which tests (what amounts to) the same thing. The first expression does not have to look at every child of the m:apply to see whether it meets the condition, and doesn't need to evaluate all those functions.

Not knowing the innards of any processor, of course, I'm only speaking in principle.

Cheers,
Wendell

At 12:15 PM 7/1/2002, you wrote:

And the complexity of the template match expressions in the stylesheets.
Simple tests on name or nodetype can be efficient but matches that involve
predicates are generally harder for a processor to index. These can cause
some processors to use sequential searching for a templates (slow for large
numbers of templates). I have seen the performance of some stylesheets
completely cripled by use of complex matches, e.g.,

<xsl:template match="m:apply[child::*[position()=1 and name()='factorof']]">

So its very specific to a processor/stylesheet pair and complex tests are
better done in for-each/if blocks if performance is more important than
maintainability.

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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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Current Thread

XSL: For-Each Efficient or Not?
- Schrooten, Ben - Mon, 1 Jul 2002 09:01:04 -0400 (EDT)
  - Oleg Tkachenko - Mon, 1 Jul 2002 09:29:44 -0400 (EDT)
  - Michael Kay - Mon, 1 Jul 2002 10:30:37 -0400 (EDT)
    - Kevin Jones - Mon, 1 Jul 2002 11:10:55 -0400 (EDT)
      - Wendell Piez - Mon, 1 Jul 2002 11:47:52 -0400 (EDT) <=
      - bryan - Mon, 1 Jul 2002 12:08:49 -0400 (EDT)
      - Johannes Döbler - Mon, 1 Jul 2002 12:57:29 -0400 (EDT)
      - Wendell Piez - Mon, 1 Jul 2002 13:57:16 -0400 (EDT)
      - Michael Kay - Mon, 1 Jul 2002 15:09:03 -0400 (EDT)

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Re: XSL: For-Each Efficient o, Kevin Jones	Thread	RE: XSL: For-Each Efficient o, bryan
Re: disable-output-escaping, Oleg Tkachenko	Date	RE: disable-output-escaping, Wendell Piez
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