Matthias Urban created XALANJ-2607:
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Summary: Improve performance 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
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 100.000
different attribute values (at least on my machine). Then it starts to get
slower and slower.
A minimally invasive solution is to make the hash table size configurable
leaving the current size the default. If an application is expected to work
with large documents, then it can increase the hash table size. For all others
nothing changes. See the patch attached to this issue. It was created using the
current trunk version of DTMStringPool.java.
Here is an example for testing.
{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();
// reduce the time needed to 3 seconds! otherwise it
will take 6 minutes!
System.setProperty("org.apache.xml.dtm.ref.DTMStringPool.hashPoolSize",
"100000");
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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