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https://issues.apache.org/jira/browse/JENA-1026?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14742315#comment-14742315
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Stian Soiland-Reyes commented on JENA-1026:
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If I understand this correctly, all OWL understanding in Jena is done by the
rule engines. No matter which engine you choose, it is still effectively
running a second programming language in interpreter mode, and therefore you
get a big performance hit compared to explicit Java code run on the JVM to deal
with OWL constructs, e.g. to determine of something is a class or property, etc.
Now my question is why this hits listIndividuals() so hard, and not
listClasses. If you try to actually iterate through the classes (e.g.
classes.toList() ) you will find this will run all the rules and also take
about 20 seconds.
20 seconds to iterate over an ontology of 4 classes is obviously not ideal - we
might want to reconsider the role of the rule system as opposed to hard-coded
rules in Java. This could be part of adding support for OWL 2 (JENA-80)
> listIndividuals performance issue
> ---------------------------------
>
> Key: JENA-1026
> URL: https://issues.apache.org/jira/browse/JENA-1026
> Project: Apache Jena
> Issue Type: Bug
> Components: Ontology API
> Affects Versions: Jena 3.0.0
> Environment: Verified on Jena 3.0.1-SNAPSHOT (2015-09-13) w/ Ubuntu
> 14.04/x64, 4 cores i7-3520M, 16G ram, SSD disk, Open JDK 1.8.0_45-internal
> Reporter: Stian Soiland-Reyes
> Priority: Minor
> Attachments: OntologiaDeAlimentos.owl,
> lpb-trace-of-not-much-food.txt, not-much-food.ttl
>
>
> As reported by Maria Clementina Latanzi on dev@jena 2015-09-12:
> {quote}
> I'm working with Jena. I have an ontology with no more than 50 individuals,
> and I use Jena to
> get individuals from Ontology by calling *listIndividual* (
> *com.hp.hpl.jena.ontology.OntModel.listIndividuals*). When I call this
> method, it's taking a lot of time up to 20 seconds. When debugging, it
> takes more than 1 minute to return. Other methods like *listClass *return
> instantly.
> {quote}
> {code}
> package testOnto;
> import java.io.InputStream;
> import java.util.ArrayList;
> import java.util.Iterator;
> import com.hp.hpl.jena.ontology.Individual;
> import com.hp.hpl.jena.ontology.OntClass;
> import com.hp.hpl.jena.ontology.OntModel;
> import com.hp.hpl.jena.rdf.model.ModelFactory;
> import com.hp.hpl.jena.rdf.model.Resource;
> import com.hp.hpl.jena.rdf.model.Property;
> import com.hp.hpl.jena.rdf.model.StmtIterator;
> import com.hp.hpl.jena.rdf.model.impl.StatementImpl;
> import com.hp.hpl.jena.shared.JenaException;
> import com.hp.hpl.jena.util.FileManager;
> import com.hp.hpl.jena.util.iterator.ExtendedIterator;
> public class onto {
> static String Ontofile =
> "C:/Users/Sig/Clemen/OntologiasArchivos/OntologiaIngesta.owl";
> public static void main(String[] args) {
> //crea ontologia
> OntModel m = ModelFactory.createOntologyModel();
> try {
> InputStream in =
> FileManager.get().open("C:/Users/Sig/Clemen/OntologiasArchivos/OntologiaDeAlimentos.owl");
> if (in ==null) {
> System.out.println("ERROR abriendo archivo" + Ontofile);
> return;
> }
> else { m.read(in, "RDF/XML");
> System.out.println("archivo" + Ontofile + "leido
> exitosamente" );
> }
> } catch (JenaException je) {
> System.out.println("ERROR leyendo archivo" + je.getMessage());
> je.printStackTrace();
> System.exit(0);
> }
> long startMilC = System.currentTimeMillis();
> System.out.println("Start list classes: " + startMilC);
> ExtendedIterator classes = m.listClasses();
> long endMilC = System.currentTimeMillis();
> System.out.println("Duration ListIndividuals: " + (endMilC -
> startMilC));
> long startMil = System.currentTimeMillis();
> System.out.println("Start ListIndividuals: " + startMil);
> ExtendedIterator individuos = m.listIndividuals();
> long endMil = System.currentTimeMillis();
> System.out.println("Duration ListIndividuals: " + (endMil -
> startMil));
> }
> }
> {code}
> See attached ontology and test case.
> Verified against current 3.0.1-SNAPSHOT.
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