[4suite] RE: XSL Performance (fwd)

[Uche Ogbuji]

Here is a very useful set of guidelines from the inestimable Mike Kay whose 
book I've already lauded here.

I hope it is useful.

--Uche

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Message-ID: <93CB64052F94D211BC5D0010A800133101FDEDC6 at wwmess3.bra01.icl.co.uk>
From: Kay Michael <Michael.Kay at icl.com>
To: "'xsl-list at mulberrytech.com'" <xsl-list at mulberrytech.com>
Subject: RE: XSL Performance
Date: Fri, 2 Jun 2000 12:47:46 +0100 
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> There hasn't really been an answer to this question yet.
> > Are there any sites that discuss XSL's performance as it 
> pertains to the XSL code. 

The simple answer to the question is "no, there aren't". But here's a quick
attempt to fill the gap, all suggestions for enhancements are welcome.

Eight tips for how to use XSLT efficiently:

1. Keep the source documents small. If necessary split the document first.
2. Keep the XSLT processor (and Java VM) loaded in memory between runs
3. If you use the same stylesheet repeatedly, compile it first.
4. If you use the same source document repeatedly, keep it in memory.
5. If you perform the same transformation repeatedly, don't. Store the
result instead.
6. Keep the output document small. For example, if you're generating HTML,
use CSS.
7. Never validate the same source document more than once.
8. Split complex transformations into several stages.

Eight tips for how to write efficient XSLT:

1. Avoid repeated use of "//item".
2. Don't evaluate the same node-set more than once; save it in a variable.
3. Avoid <xsl:number> if you can. For example, by using position().
4. Use <xsl:key>, for example to solve grouping problems.
5. Avoid complex patterns in template rules. Instead, use <xsl:choose>
within the rule.
6. Be careful when using the preceding[-sibling] or following[-sibling]
axes. This often
   indicates an algorithm with n-squared performance.
7. Don't sort the same node-set more than once. If necessary, save it as a
result tree fragment
   and access it using the node-set() extension function.
8. To output the text value of a simple #PCDATA element, use <xsl:value-of>
in preference
   to <xsl:apply-templates>.

Mike Kay


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list


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