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Re: [xsl] Streaming with XSLT version 3.0


Subject: Re: [xsl] Streaming with XSLT version 3.0
From: Michael Kay <mike@xxxxxxxxxxxx>
Date: Thu, 6 Mar 2014 20:14:56 +0000

The <xsl:copy-of> seems to be commented out.

In fact, Saxon in streaming mode doesn't currently optimize xsl:copy-of to
xsl:sequence. It's on the TODO list.

Michael Kay
Saxonica

On 6 Mar 2014, at 18:18, Eliot Kimber <ekimber@xxxxxxxxxxxx> wrote:

> Would using <xsl:sequence select="."/> rather than <xsl:copy-of
> select="."/> make a difference in this case?
>
> My understanding was that <xsl:sequence> would, under the covers, just use
> the same object (that is the input node) in the result, while copy-of
> copies the node into the output. But maybe Saxon optimizes this case and
> always just uses a pointer?
>
> Cheers,
>
> Eliot
> 
> Eliot Kimber, Owner
> Contrext, LLC
> http://contrext.com
>
>
>
>
> On 3/6/14, 10:45 AM, "Michael Kay" <mike@xxxxxxxxxxxx> wrote:
>
>>
>> On 6 Mar 2014, at 12:58, Terry Badger <terry_badger@xxxxxxxxx> wrote:
>>
>>> I have a 42 GB media and valid xml file as my source. I am using Oxygen
>>> 15.2 with Saxon ee 9.5.1.3. I am using this stylesheet which as you can
>>> see I turned off what I wanted to do to see if I could get to the end of
>>> the file. After about 45 minutes it hits my memory limit and quits. Am I
>>> doing this right or will I need to cut this elephant into pieces?
>>> Terry
>>
>> This should work. The most common reason for this kind of problem is that
>> people try to supply the input document as a conventional source document
>> as well as supplying it to xsl:stream, so it builds a tree in memory
>> anyway. However, that would normally fail much sooner than 45 minutes -
>> though you didn't say how much memory was available. Do you get a stack
>> trace at the point where it runs out of memory?
>>
>> (I know you don't want to run for 45 minutes just to find out! I find it
>> very useful when developing streaming applications to have something
>> smaller to play with, preferably about 1Gb. Of course, creating such a
>> file is much easier once you have got streaming working!)
>>
>> Michael Kay
>> Saxonica
>>
>>>
>>> <xsl:stylesheet
>>> xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>>> xmlns:xs="http://www.w3.org/2001/XMLSchema"
>>> xmlns="http://www.mediawiki.org/xml/export-0.8/"
>>> xpath-default-namespace="http://www.mediawiki.org/xml/export-0.8/"
>>> exclude-result-prefixes="#all"
>>> version="3.0">
>>> <xsl:outputmethod="xml"/>
>>> <xsl:templatename="main">
>>> <xsl:streamhref="../source/enwiki.xml">
>>> <!--  <xsl:result-document href="../out/output-wiki-02.xml">
>>> <xsl:for-each select="mediawiki">
>>> <xsl:element name="mediawiki">
>>> <xsl:for-each select="page[position() &lt; 10]">
>>> <xsl:copy-of select="."/>
>>> </xsl:for-each>
>>> </xsl:element>
>>> </xsl:for-each>
>>> </xsl:result-document>-->
>>> </xsl:stream>
>>> </xsl:template>
>>> </xsl:stylesheet>


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