Re: Lookup efficiency in XALAN?

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Subject: Re: Lookup efficiency in XALAN?
From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>
Date: Thu, 20 Nov 2003 18:05:17 -0500

J,

At 04:45 PM 11/20/2003, you wrote:

I have to do some validation in my xsl.
I'm doing the following type statement 20,000 times, and the lookup file is
around 50,000  lines of  id's <id key="XXYYZZJ"/>.
<xsl:when test="not(document('../master/ids-master.xml')/ids/id[@key=$id])">
It works for a while, then dies with an out of memory error, and it sure is
slow!

The first thing you should definitely do is collect the lookup ids into a variable, as in

<xsl:variable name="keys" select="document('../master/ids-master.xml')/ids/id/@key"/>

Then you can test your local ids against the keys in the variable, without parsing your lookup file every time (which it sounds like your processor might be doing):

<xsl:when test="not($id = $keys])">

Try that and see if it helps.

If Xalan is already optimizing the document() lookup and parse, you may get no gain from this technique -- but there's no way it could hurt.

XSLT keys could also help, but since your keys are in a separate document you'd have to switch contexts to use the XSLT key function, like so:

<xsl:key name="keys-by-id" match="id" use="@key"/>

<xsl:variable name="keyfile" select="document('../master/ids-master.xml')"/>

... and then

<xsl:for-each select="$keyfile">
  <xsl:when test="not(key('keys-by-id', $id))">...</xsl:when>
</xsl:for-each>

but whether this helps also will depend on your processor and what kind of smarts it has inside.

Cheers,
Wendell


======================================================================
Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.                http://www.mulberrytech.com
17 West Jefferson Street                    Direct Phone: 301/315-9635
Suite 207                                          Phone: 301/315-9631
Rockville, MD  20850                                 Fax: 301/315-8285
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======================================================================

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Current Thread
Lookup efficiency in XALAN? JWolpert - Thu, 20 Nov 2003 16:46:07 -0500 (EST) Wendell Piez - Thu, 20 Nov 2003 18:12:02 -0500 (EST) <= Michael Kay - Fri, 21 Nov 2003 03:06:00 -0500 (EST) <Possible follow-ups> JWolpert - Fri, 21 Nov 2003 14:57:27 -0500 (EST) Barry van Weldam - Mon, 24 Nov 2003 07:00:14 -0500 (EST) Barry van Weldam - Mon, 24 Nov 2003 07:52:13 -0500 (EST)

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Lookup efficiency in XALAN?, JWolpert	Thread	RE: Lookup efficiency in XALA, Michael Kay
Re: Including multiple XML do, Alex Hildyard	Date	Re: Including multiple XML do, Wendell Piez
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