Re: [xsl] slow xsltproc XInclude processing w/complex document?

["M. David Peterson" <m.david@xxxxxxxxxx>]

Ill give you a quick hint to help clean up your process.. I wish I had 
time to look deeper into this for you but time is not something I have a 
lot of at the moment...  None the less the first thing I noticed was the 
simple fact that you are running a for-each loop, applying each result 
element from the XPath of the select attribute of your  for each loop to 
the apply-templates which is the built in mechanism for recursion in 
XSLT... so to simplify you are going through the "for-each" process 
twice.  While I am  unsure as to the exact process implemented by 
xsltproc (not sure if it will notice the obvious doule up and ignore the 
for-each choosing instead to apply the result of the xpath expression 
directly to the apply-templates process) I can tell you there is a 
possibility that you are processing through your massive XML file which 
is implied by simply using <xsl:apply-templates 
select="document(@href)"/>...  and now that I just saw what you are 
using as your select attribute value I can definitely see why the 
compiler may not optimize ;)

I would  definitely pull out that for-each and see how much that 
helps...  As I'm looking further down I can definitely see some other 
areas that could be optimized...  I wish I had the time to help further 
but I gotta get back to coding myself...  None the less there are plenty 
of others here that will be more than happy to help you further...

Best of luck!

<M:D/>
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Paul DuBois wrote:

> I've been running some tests on a document that includes nested
> Xinclude directives. The document is complex: upwards of 1500 files,
> nested to a depth of up to 4 levels.  Total size of content is about 
> 4.8MB.
>
> For simple testing, I'm attempting only to produce a "flattened"
> document that just resolves the XIincludes.  Stylesheet looks like
> this:
>
> <?xml version="1.0" encoding="UTF-8"?>
> <xsl:stylesheet version="1.0" 
> xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
>
> <!-- Identity transform, but "flatten" xincludes -->
>
> <xsl:output method="xml" indent="yes"/>
> <xsl:preserve-space elements="*"/>
>
> <xsl:template match="xi:include" 
> xmlns:xi="http://www.w3.org/2001/XInclude";>
>   <xsl:for-each select="document(@href)">
>     <xsl:apply-templates/>
>   </xsl:for-each>
> </xsl:template>
>
> <!-- identity transform -->
>
> <xsl:template match="/ | node() | @* | comment() | 
> processing-instruction()">
>   <xsl:copy>
>     <xsl:apply-templates select="@* | node()"/>
>   </xsl:copy>
> </xsl:template>
>
> </xsl:stylesheet>
>
>
> My processing command is:
>
> xsltproc --xinclude --novalid xinclude.xsl input.xml > output.xml
>
> This takes about 12 minutes on my 900 MHz G3 iBook (Mac OS X), and about
> 4 minutes on my 2.8 GHz Pentium 4 Gentoo Linux box.
>
> That seems pretty slow, particular given that the control condition takes
> mere seconds (running the flattenedly document through a standard 
> identity
> transform with xsltproc).
>
> I don't want to post the input here because it's so big, so this is 
> really
> just a preliminary post to ask for advice as to how I might go about
> improving the XInclude-d transform: Is this a known issue with
> xsltproc/XInclude?  Or is there perhaps some flag I should be using 
> that I
> am failing to use?  Something bad about my stylesheet?
>
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