GH-4232 benchmark to try and reproduce perf difference

This benchmark uses generated data conforming to the query pattern, and
executes performance tests on both the variant with a VALUES clause, and
(as a baseline) the simple equivalent query.

Unfortunately, sofar I have been unable to reproduce any significant performance difference.

core/sail/memory/src/test/resources/benchmarkFiles/query-values.qr

@@ -0,0 +1,13 @@
+prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
+prefix owl: <http://www.w3.org/2002/07/owl#>
+
+select ?parent ?child
+where {
+    values ?type {owl:Class}
+    ?parent rdf:type ?type .
+    optional {
+        ?child rdfs:subClassOf ?parent ;
+               rdf:type ?type .
+    }
+}

core/sail/memory/src/test/resources/benchmarkFiles/query-without-values.qr

@@ -0,0 +1,12 @@
+prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
+prefix owl: <http://www.w3.org/2002/07/owl#>
+
+select ?parent ?child
+where {
+    ?parent rdf:type owl:Class .
+    optional {
+        ?child rdfs:subClassOf ?parent ;
+               rdf:type owl:Class .
+    }
+}

core/sail/nativerdf/src/test/java/org/eclipse/rdf4j/sail/nativerdf/benchmark/SPARQLValuesClauseBenchmark.java

@@ -0,0 +1,169 @@
+/*******************************************************************************
+ * Copyright (c) 2022 Eclipse RDF4J contributors.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Distribution License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *******************************************************************************/
+
+package org.eclipse.rdf4j.sail.nativerdf.benchmark;
+
+import static org.eclipse.rdf4j.model.util.Values.iri;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.commons.io.IOUtils;
+import org.eclipse.rdf4j.common.transaction.IsolationLevels;
+import org.eclipse.rdf4j.model.Model;
+import org.eclipse.rdf4j.model.util.ModelBuilder;
+import org.eclipse.rdf4j.model.vocabulary.OWL;
+import org.eclipse.rdf4j.model.vocabulary.RDF;
+import org.eclipse.rdf4j.model.vocabulary.RDFS;
+import org.eclipse.rdf4j.repository.sail.SailRepository;
+import org.eclipse.rdf4j.repository.sail.SailRepositoryConnection;
+import org.eclipse.rdf4j.sail.nativerdf.NativeStore;
+import org.junit.Rule;
+import org.junit.rules.TemporaryFolder;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Level;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.TearDown;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+/**
+ * @author Jeen Broekstra
+ */
+@State(Scope.Benchmark)
+@Warmup(iterations = 5)
+@BenchmarkMode({ Mode.AverageTime })
+@Fork(value = 1, jvmArgs = { "-Xms1G", "-Xmx1G" })
+//@Fork(value = 1, jvmArgs = {"-Xms1G", "-Xmx1G", "-XX:+UnlockCommercialFeatures", "-XX:StartFlightRecording=delay=60s,duration=120s,filename=recording.jfr,settings=profile", "-XX:FlightRecorderOptions=samplethreads=true,stackdepth=1024", "-XX:+UnlockDiagnosticVMOptions", "-XX:+DebugNonSafepoints"})
+@Measurement(iterations = 5)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+public class SPARQLValuesClauseBenchmark {
+
+	@Rule
+	public TemporaryFolder tempDir = new TemporaryFolder();
+
+	private SailRepository repository;
+
+	private static final String query_with_values_clause;
+	private static final String query_without_values_clause;
+
+	static {
+		try {
+			query_with_values_clause = IOUtils.toString(
+					getResourceAsStream("benchmarkFiles/query-values.qr"), StandardCharsets.UTF_8);
+
+			query_without_values_clause = IOUtils.toString(
+					getResourceAsStream("benchmarkFiles/query-without-values.qr"), StandardCharsets.UTF_8);
+
+		} catch (IOException e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	public static void main(String[] args) throws RunnerException, IOException, InterruptedException {
+		Options opt = new OptionsBuilder()
+				.include("SPARQLValuesClauseBenchmark") // adapt to run other benchmark tests
+				// .addProfiler("stack", "lines=20;period=1;top=20")
+				.forks(1)
+				.build();
+
+		new Runner(opt).run();
+
+	}
+
+	@Setup(Level.Trial)
+	public void beforeClass() throws IOException, InterruptedException {
+		tempDir.create();
+		File file = tempDir.newFolder();
+
+		repository = new SailRepository(new NativeStore(file, "spoc,posc,cspo,opsc"));
+
+		int numberOfItems = 10_000;
+		int numberOfChildren = 10_000;
+
+		try (var conn = repository.getConnection()) {
+			conn.begin(IsolationLevels.NONE);
+			for (int i = 0; i < numberOfItems; i++) {
+
+				var parent = iri("http://example.org/parent_" + i);
+
+				Model m = new ModelBuilder().setNamespace(OWL.NS)
+						.setNamespace("ex", "http://example.org/")
+						.subject(parent)
+						.add(RDF.TYPE, OWL.CLASS)
+						.add(RDF.TYPE, RDFS.CLASS)
+						.add(RDFS.LABEL, "parent " + i)
+						.build();
+				conn.add(m);
+				if (i % 2 == 0) {
+					for (int j = 0; j < numberOfChildren; j++) {
+						m = new ModelBuilder().setNamespace(OWL.NS)
+								.setNamespace("ex", "http://example.org/")
+								.subject("ex:child_" + i + "_" + j)
+								.add(RDF.TYPE, OWL.CLASS)
+								.add(RDF.TYPE, RDFS.CLASS)
+								.add(RDFS.SUBCLASSOF, parent)
+								.add(RDFS.LABEL, "child of " + i)
+								.build();
+						conn.add(m);
+					}
+				}
+			}
+			conn.commit();
+		}
+	}
+
+	@TearDown(Level.Trial)
+	public void afterClass() {
+		repository.shutDown();
+	}
+
+	@Benchmark
+	public long valuesOptionalQuery() {
+		try (SailRepositoryConnection connection = repository.getConnection()) {
+			return connection
+					.prepareTupleQuery(query_with_values_clause)
+					.evaluate()
+					.stream()
+					.count();
+		}
+	}
+
+	@Benchmark
+	public long simpleEquivalentQuery() {
+		try (SailRepositoryConnection connection = repository.getConnection()) {
+			return connection
+					.prepareTupleQuery(query_without_values_clause)
+					.evaluate()
+					.stream()
+					.count();
+		}
+	}
+
+	/* private methods */
+
+	private static InputStream getResourceAsStream(String filename) {
+		return SPARQLValuesClauseBenchmark.class.getClassLoader().getResourceAsStream(filename);
+	}
+}

core/sail/nativerdf/src/test/resources/benchmarkFiles/query-values.qr

@@ -0,0 +1,13 @@
+prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
+prefix owl: <http://www.w3.org/2002/07/owl#>
+
+select ?parent ?child
+where {
+    values ?type {owl:Class}
+    ?parent rdf:type ?type .
+    optional {
+        ?child rdfs:subClassOf ?parent ;
+               rdf:type ?type .
+    }
+}

core/sail/nativerdf/src/test/resources/benchmarkFiles/query-without-values.qr

@@ -0,0 +1,12 @@
+prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
+prefix owl: <http://www.w3.org/2002/07/owl#>
+
+select ?parent ?child
+where {
+    ?parent rdf:type owl:Class .
+    optional {
+        ?child rdfs:subClassOf ?parent ;
+               rdf:type owl:Class .
+    }
+}