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https://issues.apache.org/jira/browse/XALANJ-2607?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16929900#comment-16929900
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Mukul Gandhi commented on XALANJ-2607:
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I've again tested the provided patch for this issue, now using JDK 7 to build
the Xalan jar. With JDK 7, the patch provides same improvements as with JDK 8.
I've also tested that, an XSLT identity transform with the XML document
provided by the bug reporter, exhibits same improvements as with the XSLT
stylesheet & XML document provided by the bug reporter.
If we're satisfied with the functional correctness of the patch, I think
incorporating the patch into Xalan would be useful.
In general, I also agree that, we should raise the platform requirements for
Xalan to min Java 7 (it helps this patch, and I think also Xalan in general).
> Performance improvement for large documents using ID attributes
> ---------------------------------------------------------------
>
> Key: XALANJ-2607
> URL: https://issues.apache.org/jira/browse/XALANJ-2607
> Project: XalanJ2
> Issue Type: Improvement
> Security Level: No security risk; visible to anyone(Ordinary problems in
> Xalan projects. Anybody can view the issue.)
> Components: DTM
> Affects Versions: 2.7.2
> Environment: Tested on but not limited to: Windows, x64, JRE 1.8
> Reporter: Matthias Urban
> Assignee: Steven J. Hathaway
> Priority: Major
> Attachments: DTMStringPool.patch
>
>
> XalanJ gets very slow for large XML documents using ID attributes often used
> in article lists. If, for instance, an article list with 1.000.000 entries is
> parsed, then it takes 6 minutes (on my machine) just to build the DTM. This
> is due to a design decision in DTMStringPool utilizing a fixed size hash
> table of 101 entries. This works astoundingly well for documents with less
> than 10.000 different attribute values. Then it starts to get slower and
> slower.
> I've tested multiple solutions, like to increase the hash table size to
> 100.000 and 1.000.000 (overkill for everyday documents), or make it
> configurable leaving the current size the default (needs to introduce a
> 'backdoor' system property). In the end the best solution was to use a simple
> HashMap for the string lookup. It proved to be as fast as the fixed size
> table combined with a very good scalability. See the patch attached to this
> issue. It was created using the current trunk version of DTMStringPool.java.
> Here is an example for testing. Without the patch applied it takes about 6
> minutes to finish. With the patch applied it only takes 3 seconds!
> {code:title=Test.java}
> import java.io.File;
> import java.io.FileOutputStream;
> import java.io.FileWriter;
> import java.util.Date;
> import javax.xml.transform.Transformer;
> import javax.xml.transform.TransformerFactory;
> import javax.xml.transform.stream.StreamResult;
> import javax.xml.transform.stream.StreamSource;
> public class Test {
> public static void main(String[] args) {
> try {
> File xmlfile = new File("doc.xml");
> FileWriter fout = new FileWriter(xmlfile);
> fout.write("<catalogue>\n");
> for (int i = 0; i < 1000000; i++) {
> fout.append("<article id=\"" + i + "\">articlename</article>\n");
> }
> fout.write("</catalogue>");
> fout.close();
> System.out.println("Start : " + new Date());
> TransformerFactory factory = TransformerFactory.newInstance();
> Transformer transformer = factory.newTransformer(new StreamSource(new
> File("script.xsl")));
> transformer.transform(new StreamSource(xmlfile), new StreamResult(new
> FileOutputStream("out.txt")));
> System.out.println("End : " + new Date());
> }
> catch (Exception e) {
> e.printStackTrace();
> }
> }
> }
> {code}
> {code:xml|title=script.xsl}
> <?xml version="1.0"?>
> <xsl:stylesheet version="1.0"
> xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
> <xsl:output method="text"/>
> <xsl:template match="text()|@*"/>
> <xsl:template match="/">
> <xsl:apply-templates select="*"/>
> </xsl:template>
> <xsl:template match="article">
> <xsl:value-of select="@id"/>
> <xsl:text> </xsl:text>
> </xsl:template>
> </xsl:stylesheet>
> {code}
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