GH-5447 LMDB Store query performance improvements (#5456)

Author: hmottestad

AGENTS.md

@@ -12,7 +12,6 @@
 package org.eclipse.rdf4j.collection.factory.impl;
 
 import java.io.Serializable;
-import java.util.Arrays;
 import java.util.List;
 
 import org.eclipse.rdf4j.collection.factory.api.BindingSetKey;
@@ -22,12 +21,12 @@ public class DefaultBindingSetKey implements BindingSetKey, Serializable {
 
 	private static final long serialVersionUID = 1;
 
-	private final Value[] values;
+	private final List<Value> values;
 
 	private final int hash;
 
 	public DefaultBindingSetKey(List<Value> values, int hash) {
-		this.values = values.toArray(new Value[0]);
+		this.values = values;
 		this.hash = hash;
 	}
 
@@ -39,7 +38,7 @@ public int hashCode() {
 	@Override
 	public boolean equals(Object other) {
 		if (other instanceof DefaultBindingSetKey && other.hashCode() == hash) {
-			return Arrays.deepEquals(values, ((DefaultBindingSetKey) other).values);
+			return values.equals(((DefaultBindingSetKey) other).values);
 		}
 		return false;
 	}

core/collection-factory/api/src/main/java/org/eclipse/rdf4j/collection/factory/impl/DefaultBindingSetKey.java

@@ -14,6 +14,8 @@
 import java.util.Iterator;
 import java.util.stream.Stream;
 
+import org.eclipse.rdf4j.model.Statement;
+
 /**
  * An {@link CloseableIteration} that can be closed to free resources that it is holding. CloseableIterations
  * automatically free their resources when exhausted. If not read until exhaustion or if you want to make sure the
@@ -33,6 +35,8 @@
  */
 public interface CloseableIteration<E> extends Iterator<E>, AutoCloseable {
 
+	EmptyIteration<Statement> EMPTY_STATEMENT_ITERATION = new EmptyIteration<>();
+
 	/**
 	 * Convert the results to a Java 8 Stream.
 	 *

core/common/iterator/src/main/java/org/eclipse/rdf4j/common/iteration/CloseableIteration.java

@@ -50,7 +50,11 @@ public DualUnionIteration(Comparator<E> cmp,
 	public static <E> CloseableIteration<? extends E> getWildcardInstance(
 			CloseableIteration<? extends E> leftIteration, CloseableIteration<? extends E> rightIteration) {
 
-		if (rightIteration instanceof EmptyIteration) {
+		if (leftIteration == EMPTY_STATEMENT_ITERATION) {
+			return rightIteration;
+		} else if (rightIteration == EMPTY_STATEMENT_ITERATION) {
+			return leftIteration;
+		} else if (rightIteration instanceof EmptyIteration) {
 			return leftIteration;
 		} else if (leftIteration instanceof EmptyIteration) {
 			return rightIteration;
@@ -63,7 +67,11 @@ public static <E> CloseableIteration<? extends E> getWildcardInstance(
 	public static <E> CloseableIteration<? extends E> getWildcardInstance(Comparator<E> cmp,
 			CloseableIteration<? extends E> leftIteration, CloseableIteration<? extends E> rightIteration) {
 
-		if (rightIteration instanceof EmptyIteration) {
+		if (leftIteration == EMPTY_STATEMENT_ITERATION) {
+			return rightIteration;
+		} else if (rightIteration == EMPTY_STATEMENT_ITERATION) {
+			return leftIteration;
+		} else if (rightIteration instanceof EmptyIteration) {
 			return leftIteration;
 		} else if (leftIteration instanceof EmptyIteration) {
 			return rightIteration;
@@ -75,7 +83,11 @@ public static <E> CloseableIteration<? extends E> getWildcardInstance(Comparator
 	public static <E> CloseableIteration<E> getInstance(CloseableIteration<E> leftIteration,
 			CloseableIteration<E> rightIteration) {
 
-		if (rightIteration instanceof EmptyIteration) {
+		if (leftIteration == EMPTY_STATEMENT_ITERATION) {
+			return rightIteration;
+		} else if (rightIteration == EMPTY_STATEMENT_ITERATION) {
+			return leftIteration;
+		} else if (rightIteration instanceof EmptyIteration) {
 			return leftIteration;
 		} else if (leftIteration instanceof EmptyIteration) {
 			return rightIteration;

core/common/iterator/src/main/java/org/eclipse/rdf4j/common/iteration/DualUnionIteration.java

@@ -27,6 +27,11 @@ default boolean isBNode() {
 		return true;
 	}
 
+	@Override
+	default Type getType() {
+		return Value.Type.BNode;
+	}
+
 	/**
 	 * Retrieves this blank node's identifier.
 	 *

core/model-api/src/main/java/org/eclipse/rdf4j/model/BNode.java

@@ -38,6 +38,11 @@ default boolean isIRI() {
 		return true;
 	}
 
+	@Override
+	default Type getType() {
+		return Value.Type.IRI;
+	}
+
 	/**
 	 * Gets the namespace part of this IRI.
 	 * <p>

core/model-api/src/main/java/org/eclipse/rdf4j/model/IRI.java

@@ -47,6 +47,11 @@ default boolean isLiteral() {
 		return true;
 	}
 
+	@Override
+	default Type getType() {
+		return Value.Type.Literal;
+	}
+
 	/**
 	 * Gets the label (the lexical value) of this literal.
 	 *

core/model-api/src/main/java/org/eclipse/rdf4j/model/Literal.java

@@ -33,6 +33,11 @@ default boolean isTriple() {
 		return true;
 	}
 
+	@Override
+	default Type getType() {
+		return Value.Type.Triple;
+	}
+
 	/**
 	 * Gets the subject of this triple.
 	 *

core/model-api/src/main/java/org/eclipse/rdf4j/model/Triple.java

@@ -17,6 +17,13 @@
  */
 public interface Value extends Serializable {
 
+	enum Type {
+		IRI,
+		BNode,
+		Literal,
+		Triple
+	}
+
 	/**
 	 * Check if the object is an instance of the given type. Typically 2x than using instanceof.
 	 * <p>
@@ -72,6 +79,21 @@ default boolean isTriple() {
 		return false;
 	}
 
+	default Type getType() {
+
+		if (isIRI()) {
+			return Type.IRI;
+		} else if (isBNode()) {
+			return Type.BNode;
+		} else if (isLiteral()) {
+			return Type.Literal;
+		} else if (isTriple()) {
+			return Type.Triple;
+		} else {
+			throw new IllegalStateException("Unknown value type");
+		}
+	}
+
 	/**
 	 * Returns the String-value of a <var>Value</var> object. This returns either a {@link Literal}'s label, a
 	 * {@link IRI}'s URI or a {@link BNode}'s ID.

core/model-api/src/main/java/org/eclipse/rdf4j/model/Value.java

@@ -155,6 +155,16 @@ public interface ValueFactory {
 	 */
 	Literal createLiteral(long value);
 
+	/**
+	 * Creates a new typed numerical literal representing the specified value.
+	 *
+	 * @param value The value for the literal.
+	 * @param xsd   The XSD datatype to use.
+	 */
+	default Literal createLiteral(long value, CoreDatatype.XSD xsd) {
+		return createLiteral(Long.toString(value), xsd);
+	}
+
 	/**
 	 * Creates a new <var>xsd:float</var>-typed literal representing the specified value.
 	 *