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https://issues.apache.org/jira/browse/XERCESJ-1276?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13593297#comment-13593297
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Jens Dittrich commented on XERCESJ-1276:
----------------------------------------
All,
I did some work on the Xerces-J 2.11 sources and did the following changes:
* implement a TreeSet<List<Comparable>> for storing tuples of unique
constraints and key constraints in XMLSchemaValidator$ValuationStoreBase.
* I rather decided to not use a HashSet as my use case requires dynamically
extendable datastructures as I am validating using JAXB on the fly and I do not
know the number of entries. As I understand the HashMap::resize implementation
it runs with O(n), right?
* I made any interface in org.apache.xerces.xs.datatypes extending
java.util.Comparable and implemented the respective operations in
org.apache.xerces.impl.dv.* when required via lexicographical comparism, see
ObjectListImpl.compareTo for instance.
* I had to add some casts in the class XSSimpleTypeDecl and one in
SchemaGrammar. That is where I expect ClassCastExceptions during the Xerces
Unit Tests that are not available to me.
Regards,
Jens.
> Improve performance of XML Schema Identity-constraint validation ---
> XMLSchemaValidator$ValueStoreBase.contains() is painfully slow.
> ------------------------------------------------------------------------------------------------------------------------------------
>
> Key: XERCESJ-1276
> URL: https://issues.apache.org/jira/browse/XERCESJ-1276
> Project: Xerces2-J
> Issue Type: Bug
> Components: XML Schema 1.0 Structures
> Affects Versions: 2.6.2, 2.9.1
> Reporter: Kenny MacLeod
> Labels: gsoc, gsoc2013, mentor
> Attachments: Xerces-J-src.2.11.0_patch1276.txt,
> XMLSchemaValidator.java
>
>
> Under certain conditions, the contains() method in
> XMLSchemaValidator$ValueStoreBase can cripple the performance of parsing and
> validation.
> I'm not sure what those conditions are, but as a guideline figure I was using
> JAXB2 to deserialize a 22meg XML file. Without schema validation, it took 5
> seconds. With validation, it took over 3 minutes (JDK 1.5.0_10 on win32). My
> profiler pointed the finger squarely at that method XMLSchemaValidator.
> Suspicions were aroused further when seeing this comment in the source:
> public boolean contains() {
> // REVISIT: we can improve performance by using hash codes,
> instead of
> // traversing global vector that could be quite large.
> This is present in Xerces 2.6.2 contained with JDK1.5.0_10, and also in the
> source for 2.9.1.
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