[jira] [Commented] (JENA-2325) Performance optimization for SPARQ Path Alternative

["Andy Seaborne (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JENA-2325?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17636188#comment-17636188 ] 

Andy Seaborne commented on JENA-2325:
-------------------------------------

This has been taken up on GitHub [jena/issues/1629|https://github.com/apache/jena/issues/1629] from [https://github.com/apache/jena/issues/1614]
and in PRs [#1616|https://github.com/apache/jena/pulls/1616] [#1620.|https://github.com/apache/jena/pulls/1620]

 

> Performance optimization for SPARQ Path Alternative
> ---------------------------------------------------
>
>                 Key: JENA-2325
>                 URL: https://issues.apache.org/jira/browse/JENA-2325
>             Project: Apache Jena
>          Issue Type: Improvement
>          Components: ARQ
>    Affects Versions: Jena 4.4.0
>            Reporter: Jan Martin Keil
>            Priority: Major
>              Labels: performance
>
> The execution time of equivalent SPARQL queries using [Path Alternative|https://www.w3.org/TR/sparql11-query/#rPathAlternative] or [UNION|https://www.w3.org/TR/sparql11-query/#rGroupOrUnionGraphPattern] differ considerably. Example:
> {code:sql}
> SELECT * WHERE {?a <http://example.org/property1>|<http://example.org/property2> ?b}
> {code}
> {code:sql}
> SELECT * WHERE {{?a <http://example.org/property1> ?b } UNION { ?a <http://example.org/property2> ?b}}
> {code}
> Java MWE with 100000 bindings for each alternative:
> {code:java}
> import org.apache.jena.query.Query;
> import org.apache.jena.query.QueryExecutionFactory;
> import org.apache.jena.query.QueryFactory;
> import org.apache.jena.rdf.model.Model;
> import org.apache.jena.rdf.model.ModelFactory;
> import org.apache.jena.rdf.model.Property;
> import org.apache.jena.rdf.model.ResourceFactory;
> import org.junit.jupiter.api.Test;
> public class PathAlternativeVsUnion {
> 	@Test
> 	public void compare() {
> 		Model model = ModelFactory.createDefaultModel();
> 		int scale = 100000;
> 		Property property1 = ResourceFactory.createProperty("http://example.org/property1");
> 		Property property2 = ResourceFactory.createProperty("http://example.org/property2");
> 		for (int i = 0; i < scale; i++) {
> 			model.createResource("http://example.org/r" + i).addProperty(property1,
> 					ResourceFactory.createResource("http://example.org/r" + (scale + i)));
> 			model.createResource("http://example.org/r" + (scale * 2 + i)).addProperty(property2,
> 					ResourceFactory.createResource("http://example.org/r" + (scale * 3 + i)));
> 		}
> 		Query pathAlternativeQuery = QueryFactory.create("SELECT * WHERE {?a <" + property1 + ">|<" + property2 + "> ?b}");
> 		Query unionQuery = QueryFactory
> 				.create("SELECT * WHERE {{?a <" + property1 + "> ?b } UNION { ?a <" + property2 + "> ?b}}");
> 		// warm up pathAlternativeQuery
> 		QueryExecutionFactory.create(pathAlternativeQuery, model).execSelect().forEachRemaining(qs -> {
> 			/* consume but do nothing */});
> 		// measure pathAlternativeQuery
> 		long start = System.currentTimeMillis();
> 		QueryExecutionFactory.create(pathAlternativeQuery, model).execSelect().forEachRemaining(qs -> {
> 			/* consume but do nothing */});
> 		long finish = System.currentTimeMillis();
> 		System.out.println("Time pathAlternativeQuery: " + (finish - start) + " ms");
> 		// warm up unionQuery
> 		QueryExecutionFactory.create(unionQuery, model).execSelect().forEachRemaining(qs -> {
> 			/* consume but do nothing */});
> 		// measure unionQuery
> 		start = System.currentTimeMillis();
> 		QueryExecutionFactory.create(unionQuery, model).execSelect().forEachRemaining(qs -> {
> 			/* consume but do nothing */});
> 		finish = System.currentTimeMillis();
> 		System.out.println("Time unionQuery:           " + (finish - start) + " ms");
> 	}
> }
> {code}
> Result:
> {code:java}
> Time pathAlternativeQuery: 10940 ms
> Time unionQuery:           145 ms
> {code}
> Is it possible to add some automatic execution plan optimization for that to Apache Jena?



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