more potential optimisations

Author: hmottestad

core/queryalgebra/evaluation/src/main/java/org/eclipse/rdf4j/query/algebra/evaluation/iterator/JoinKeyCacheIterator.java

@@ -112,18 +112,19 @@ private CacheEntry evaluateRight(BindingSet leftBindings) {
 			return CacheEntry.empty();
 		}
 		List<BindingSet> results = new ArrayList<>();
+		boolean cacheable = true;
 		try {
 			while (iteration.hasNext()) {
 				BindingSet candidate = iteration.next();
 				results.add(stripLeftBindings(candidate));
 				if (maxResultsPerKey > 0 && results.size() > maxResultsPerKey) {
-					return new CacheEntry(results, false);
+					cacheable = false;
 				}
 			}
 		} finally {
 			iteration.close();
 		}
-		return new CacheEntry(results, true);
+		return new CacheEntry(results, cacheable);
 	}
 
 	private BindingSet stripLeftBindings(BindingSet candidate) {

core/queryalgebra/evaluation/src/main/java/org/eclipse/rdf4j/query/algebra/evaluation/iterator/LeftJoinKeyCacheIterator.java

@@ -117,18 +117,19 @@ private CacheEntry evaluateRight(BindingSet leftBindings) {
 			return CacheEntry.empty();
 		}
 		List<BindingSet> results = new ArrayList<>();
+		boolean cacheable = true;
 		try {
 			while (iteration.hasNext()) {
 				BindingSet candidate = iteration.next();
 				results.add(stripLeftBindings(candidate));
 				if (maxResultsPerKey > 0 && results.size() > maxResultsPerKey) {
-					return new CacheEntry(results, false);
+					cacheable = false;
 				}
 			}
 		} finally {
 			iteration.close();
 		}
-		return new CacheEntry(results, true);
+		return new CacheEntry(results, cacheable);
 	}
 
 	private BindingSet stripLeftBindings(BindingSet candidate) {

core/queryalgebra/evaluation/src/main/java/org/eclipse/rdf4j/query/algebra/evaluation/optimizer/SparqlUoOptimizer.java

@@ -66,7 +66,9 @@ public SparqlUoOptimizer(EvaluationStatistics evaluationStatistics, SparqlUoConf
 	public void optimize(TupleExpr tupleExpr, Dataset dataset, BindingSet bindings) {
 		PARENT_REFERENCE_CLEANER.optimize(tupleExpr, dataset, bindings);
 		tupleExpr.visit(new SparqlUoVisitor());
-		optionalFilterJoinOptimizer.optimize(tupleExpr, dataset, bindings);
+		if (config.enableOptionalFilterJoin()) {
+			optionalFilterJoinOptimizer.optimize(tupleExpr, dataset, bindings);
+		}
 	}
 
 	private class SparqlUoVisitor extends AbstractQueryModelVisitor<RuntimeException> {

core/queryalgebra/evaluation/src/main/java/org/eclipse/rdf4j/query/algebra/evaluation/optimizer/SparqlUoQueryOptimizerPipeline.java

@@ -32,6 +32,7 @@ public class SparqlUoQueryOptimizerPipeline implements QueryOptimizerPipeline {
 	private final MinusOptimizer minusOptimizer;
 	private final ExistsConstantOptimizer existsConstantOptimizer;
 	private final QueryJoinOptimizer joinOptimizer;
+	private final boolean enableOptionalFilterJoin;
 
 	public SparqlUoQueryOptimizerPipeline(EvaluationStrategy strategy, TripleSource tripleSource,
 			EvaluationStatistics evaluationStatistics) {
@@ -51,6 +52,7 @@ public SparqlUoQueryOptimizerPipeline(EvaluationStrategy strategy, TripleSource
 		this.existsConstantOptimizer = new ExistsConstantOptimizer();
 		this.joinOptimizer = new QueryJoinOptimizer(evaluationStatistics, strategy.isTrackResultSize(), tripleSource,
 				false);
+		this.enableOptionalFilterJoin = config.enableOptionalFilterJoin();
 	}
 
 	@Override
@@ -73,7 +75,9 @@ public Iterable<QueryOptimizer> getOptimizers() {
 			if (optimizer instanceof FilterOptimizer) {
 				optimizers.add(optimizer);
 				optimizers.add(unionCommonFilterBindingSetOptimizer);
-				optimizers.add(optionalFilterJoinOptimizer);
+				if (enableOptionalFilterJoin) {
+					optimizers.add(optionalFilterJoinOptimizer);
+				}
 				if (!statementPatternInserted) {
 					optimizers.add(unionCommonStatementPatternOptimizer);
 					statementPatternInserted = true;

core/queryalgebra/evaluation/src/main/java/org/eclipse/rdf4j/query/algebra/evaluation/optimizer/sparqluo/SparqlUoConfig.java

@@ -21,6 +21,7 @@ public final class SparqlUoConfig {
 	public static final String PROP_SIMULATE_JOIN_ORDER = "rdf4j.sparqluo.simulateJoinOrder";
 	public static final String PROP_MAX_BSA_UNION_DISTRIBUTION = "rdf4j.sparqluo.maxBindingSetAssignmentUnionSize";
 	public static final String PROP_ENABLE_MINUS_UNION_SPLIT = "rdf4j.sparqluo.enableMinusUnionSplit";
+	public static final String PROP_ENABLE_OPTIONAL_FILTER_JOIN = "rdf4j.sparqluo.enableOptionalFilterJoin";
 
 	public static final boolean DEFAULT_ALLOW_NON_IMPROVING = false;
 	public static final double DEFAULT_VAR_DOMAIN = 10.0;
@@ -30,6 +31,7 @@ public final class SparqlUoConfig {
 	public static final boolean DEFAULT_SIMULATE_JOIN_ORDER = true;
 	public static final int DEFAULT_MAX_BSA_UNION_DISTRIBUTION = 32;
 	public static final boolean DEFAULT_ENABLE_MINUS_UNION_SPLIT = true;
+	public static final boolean DEFAULT_ENABLE_OPTIONAL_FILTER_JOIN = true;
 
 	private final boolean allowNonImprovingTransforms;
 	private final double assumedVarDomainCardinality;
@@ -39,6 +41,7 @@ public final class SparqlUoConfig {
 	private final boolean simulateJoinOrder;
 	private final int maxBindingSetAssignmentUnionSize;
 	private final boolean enableMinusUnionSplit;
+	private final boolean enableOptionalFilterJoin;
 
 	private SparqlUoConfig(Builder builder) {
 		this.allowNonImprovingTransforms = builder.allowNonImprovingTransforms;
@@ -50,6 +53,7 @@ private SparqlUoConfig(Builder builder) {
 		this.maxBindingSetAssignmentUnionSize = nonNegativeOrDefault(builder.maxBindingSetAssignmentUnionSize,
 				DEFAULT_MAX_BSA_UNION_DISTRIBUTION);
 		this.enableMinusUnionSplit = builder.enableMinusUnionSplit;
+		this.enableOptionalFilterJoin = builder.enableOptionalFilterJoin;
 	}
 
 	public static SparqlUoConfig defaultConfig() {
@@ -90,6 +94,10 @@ public static SparqlUoConfig fromSystemProperties() {
 		if (enableMinusUnionSplit != null) {
 			builder.enableMinusUnionSplit(enableMinusUnionSplit);
 		}
+		Boolean enableOptionalFilterJoin = readBoolean(PROP_ENABLE_OPTIONAL_FILTER_JOIN);
+		if (enableOptionalFilterJoin != null) {
+			builder.enableOptionalFilterJoin(enableOptionalFilterJoin);
+		}
 		return builder.build();
 	}
 
@@ -129,6 +137,10 @@ public boolean enableMinusUnionSplit() {
 		return enableMinusUnionSplit;
 	}
 
+	public boolean enableOptionalFilterJoin() {
+		return enableOptionalFilterJoin;
+	}
+
 	private static Boolean readBoolean(String property) {
 		String value = System.getProperty(property);
 		if (value == null) {
@@ -182,6 +194,7 @@ public static final class Builder {
 		private boolean simulateJoinOrder = DEFAULT_SIMULATE_JOIN_ORDER;
 		private int maxBindingSetAssignmentUnionSize = DEFAULT_MAX_BSA_UNION_DISTRIBUTION;
 		private boolean enableMinusUnionSplit = DEFAULT_ENABLE_MINUS_UNION_SPLIT;
+		private boolean enableOptionalFilterJoin = DEFAULT_ENABLE_OPTIONAL_FILTER_JOIN;
 
 		private Builder() {
 		}
@@ -226,6 +239,11 @@ public Builder enableMinusUnionSplit(boolean enableMinusUnionSplit) {
 			return this;
 		}
 
+		public Builder enableOptionalFilterJoin(boolean enableOptionalFilterJoin) {
+			this.enableOptionalFilterJoin = enableOptionalFilterJoin;
+			return this;
+		}
+
 		public SparqlUoConfig build() {
 			return new SparqlUoConfig(this);
 		}