[jira] [Created] (JENA-1290) Slow Model.createList()

["Alexis Armin Huf (JIRA)" <ji...@apache.org>]

Alexis Armin Huf created JENA-1290:
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             Summary: Slow Model.createList()
                 Key: JENA-1290
                 URL: https://issues.apache.org/jira/browse/JENA-1290
             Project: Apache Jena
          Issue Type: Improvement
          Components: Core
    Affects Versions: Jena 3.2.0, Jena 3.0.1
         Environment: OpenJDK 1.8.0.121-b13
            Reporter: Alexis Armin Huf
            Priority: Minor


Model.createList(Iterator) is slow for large list sizes. Starting at 128 nodes, creating a list from an ArrayList iterator takes ~3.6ms and the time goes up to 182ms for 1024 nodes. Creating the RDF list by hand and then doing .as(RDFList.class) for the 1024-nodes tests takes only 1.2ms. I will attach a MWE.

Going through the code, the cause seems to be that RDFListImpl.with() , which is called for every member added, will always walk the entire list to get the last node. It mentions a possible cache for that, but it is not implemented. I wrote a patch for this issue replacing ModelCom.createList() implementation. I could not find tests for createList, so I added three simple ones to TestModel.

PS: I'm having a classpath issue with jena-arq tests on mvn clean install, so I could only run tests for jena-core. Are there specific more instructions somewhere for building and testing jena?




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