perf: GH-5715 optimize query evaluation hot paths

Author: hmottestad

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

@@ -76,13 +76,7 @@ public DistinctIteration(CloseableIteration<? extends E> iter, Supplier<Set<E>>
 	 */
 	@Override
 	protected boolean accept(E object) {
-		if (inExcludeSet(object)) {
-			// object has already been returned
-			return false;
-		} else {
-			add(object);
-			return true;
-		}
+		return add(object);
 	}
 
 	@Override

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

@@ -8,8 +8,11 @@
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *******************************************************************************/
+// Some portions generated by Codex
 package org.eclipse.rdf4j.query.algebra.evaluation;
 
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -43,9 +46,24 @@ public class ArrayBindingSet extends AbstractBindingSet implements MutableBindin
 
 	private static final long serialVersionUID = -1L;
 
+	@FunctionalInterface
+	public interface SortedBindingNamesCache {
+		List<String> get(long activeBindingMask);
+	}
+
 	private static final Logger logger = LoggerFactory.getLogger(ArrayBindingSet.class);
 	private static final Value NULL_VALUE = Values
 			.iri("urn:null:d57c56f3-41a9-468e-8dce-5706ebdef84c_e88d9e52-27cb-4056-a889-1ea353fa6f0c");
+	private static final VarHandle LAST_EQUALS_MISMATCH_INDEX;
+	private static int lastEqualsMismatchIndex;
+	static {
+		try {
+			LAST_EQUALS_MISMATCH_INDEX = MethodHandles.lookup()
+					.findStaticVarHandle(ArrayBindingSet.class, "lastEqualsMismatchIndex", int.class);
+		} catch (ReflectiveOperationException e) {
+			throw new ExceptionInInitializerError(e);
+		}
+	}
 
 	private final String[] bindingNames;
 
@@ -54,6 +72,9 @@ public class ArrayBindingSet extends AbstractBindingSet implements MutableBindin
 	private boolean empty;
 
 	private final Value[] values;
+	private final SortedBindingNamesCache sharedSortedBindingNamesCache;
+	private long activeBindingMask;
+	private int cachedSize = -1;
 	private int cachedHashCode;
 
 	/**
@@ -64,16 +85,29 @@ public class ArrayBindingSet extends AbstractBindingSet implements MutableBindin
 	 * @param names The binding names.
 	 */
 	public ArrayBindingSet(String... names) {
+		this(names, null);
+	}
+
+	public ArrayBindingSet(String[] names, SortedBindingNamesCache sharedSortedBindingNamesCache) {
 		this.bindingNames = names;
 		this.values = new Value[names.length];
+		this.sharedSortedBindingNamesCache = sharedSortedBindingNamesCache;
 		this.empty = true;
+		this.cachedSize = 0;
 	}
 
 	public ArrayBindingSet(BindingSet toCopy, Set<String> names, String[] namesArray) {
+		this(toCopy, names, namesArray, null);
+	}
+
+	public ArrayBindingSet(BindingSet toCopy, Set<String> names, String[] namesArray,
+			SortedBindingNamesCache sharedSortedBindingNamesCache) {
 		assert !(toCopy instanceof ArrayBindingSet);
 
 		this.bindingNames = namesArray;
 		this.values = new Value[this.bindingNames.length];
+		this.sharedSortedBindingNamesCache = sharedSortedBindingNamesCache;
+		int size = 0;
 		for (int i = 0; i < this.bindingNames.length; i++) {
 			Binding binding = toCopy.getBinding(this.bindingNames[i]);
 
@@ -82,20 +116,36 @@ public ArrayBindingSet(BindingSet toCopy, Set<String> names, String[] namesArray
 				if (this.values[i] == null) {
 					this.values[i] = NULL_VALUE;
 				}
+				size++;
 			} else if (hasBinding(this.bindingNames[i])) {
 				this.values[i] = NULL_VALUE;
+				size++;
 			}
 		}
 		this.empty = toCopy.isEmpty();
+		this.cachedSize = this.empty ? 0 : size;
+		if (sharedSortedBindingNamesCache != null) {
+			this.activeBindingMask = calculateActiveBindingMask();
+		}
 		assert !this.empty || size() == 0;
 
 	}
 
 	public ArrayBindingSet(ArrayBindingSet toCopy, String... names) {
+		this(toCopy, names, null);
+	}
+
+	public ArrayBindingSet(ArrayBindingSet toCopy, String[] names,
+			SortedBindingNamesCache sharedSortedBindingNamesCache) {
 		this.bindingNames = names;
 
 		this.values = Arrays.copyOf(toCopy.values, toCopy.values.length);
+		this.sharedSortedBindingNamesCache = sharedSortedBindingNamesCache;
 		this.empty = toCopy.empty;
+		this.cachedSize = toCopy.cachedSize;
+		if (sharedSortedBindingNamesCache != null) {
+			this.activeBindingMask = calculateActiveBindingMask();
+		}
 		assert !this.empty || size() == 0;
 	}
 
@@ -117,6 +167,7 @@ public BiConsumer<Value, ArrayBindingSet> getDirectSetBinding(String bindingName
 		return (v, a) -> {
 			a.values[index] = v == null ? NULL_VALUE : v;
 			a.empty = false;
+			a.updateActiveBindingMask(index, true);
 			a.clearCache();
 		};
 	}
@@ -132,6 +183,7 @@ public BiConsumer<Value, ArrayBindingSet> getDirectAddBinding(String bindingName
 			assert a.values[index] == null;
 			a.values[index] = v == null ? NULL_VALUE : v;
 			a.empty = false;
+			a.updateActiveBindingMask(index, true);
 			a.clearCache();
 		};
 
@@ -280,18 +332,23 @@ public Iterator<Binding> iterator() {
 	@Override
 	public int size() {
 		if (isEmpty()) {
+			cachedSize = 0;
 			return 0;
 		}
 
-		int size = 0;
+		if (cachedSize == -1) {
+			int size = 0;
 
-		for (Value value : values) {
-			if (value != null) {
-				size++;
+			for (Value value : values) {
+				if (value != null) {
+					size++;
+				}
 			}
+
+			cachedSize = size;
 		}
 
-		return size;
+		return cachedSize;
 	}
 
 	@Override
@@ -355,23 +412,28 @@ private boolean slowIsCompatible(BindingSet other) {
 	public List<String> getSortedBindingNames() {
 
 		if (sortedBindingNames == null) {
-			int size = size();
-
-			if (size == 1) {
-				for (int i = 0; i < bindingNames.length; i++) {
-					if (values[i] != null) {
-						sortedBindingNames = Collections.singletonList(bindingNames[i]);
-					}
-				}
+			if (sharedSortedBindingNamesCache != null) {
+				sortedBindingNames = sharedSortedBindingNamesCache.get(activeBindingMask);
 			} else {
-				ArrayList<String> names = new ArrayList<>(size);
-				for (int i = 0; i < bindingNames.length; i++) {
-					if (values[i] != null) {
-						names.add(bindingNames[i]);
+				int size = size();
+
+				if (size == 1) {
+					for (int i = 0; i < bindingNames.length; i++) {
+						if (values[i] != null) {
+							sortedBindingNames = Collections.singletonList(bindingNames[i]);
+							break;
+						}
+					}
+				} else {
+					ArrayList<String> names = new ArrayList<>(size);
+					for (int i = 0; i < bindingNames.length; i++) {
+						if (values[i] != null) {
+							names.add(bindingNames[i]);
+						}
 					}
+					names.sort(String::compareTo);
+					sortedBindingNames = names;
 				}
-				names.sort(String::compareTo);
-				sortedBindingNames = names;
 			}
 		}
 
@@ -393,6 +455,7 @@ public void addBinding(Binding binding) {
 		assert this.values[index] == null;
 		this.values[index] = value == null ? NULL_VALUE : value;
 		empty = false;
+		updateActiveBindingMask(index, true);
 		clearCache();
 	}
 
@@ -405,6 +468,7 @@ public void setBinding(Binding binding) {
 		Value value = binding.getValue();
 		this.values[index] = value == null ? NULL_VALUE : value;
 		empty = false;
+		updateActiveBindingMask(index, true);
 		clearCache();
 	}
 
@@ -416,6 +480,7 @@ public void setBinding(String name, Value value) {
 		}
 
 		this.values[index] = value;
+		updateActiveBindingMask(index, value != null);
 		if (value == null) {
 			this.empty = true;
 			for (Value value1 : this.values) {
@@ -437,6 +502,8 @@ public boolean isEmpty() {
 
 	private void clearCache() {
 		bindingNamesSetCache = null;
+		sortedBindingNames = null;
+		cachedSize = -1;
 		cachedHashCode = 0;
 	}
 
@@ -459,7 +526,33 @@ public void addAll(ArrayBindingSet other) {
 		}
 
 		clearCache();
+		if (sharedSortedBindingNamesCache != null) {
+			activeBindingMask = calculateActiveBindingMask();
+		}
+
+	}
+
+	private void updateActiveBindingMask(int index, boolean hasValue) {
+		if (sharedSortedBindingNamesCache == null) {
+			return;
+		}
+
+		long maskBit = 1L << index;
+		if (hasValue) {
+			activeBindingMask |= maskBit;
+		} else {
+			activeBindingMask &= ~maskBit;
+		}
+	}
 
+	private long calculateActiveBindingMask() {
+		long mask = 0L;
+		for (int i = 0; i < values.length; i++) {
+			if (values[i] != null) {
+				mask |= 1L << i;
+			}
+		}
+		return mask;
 	}
 
 	@Override
@@ -495,9 +588,20 @@ public boolean equals(Object other) {
 		}
 
 		if (bindingNames == o.bindingNames) {
-			for (int i = 0; i < values.length; i++) {
-				if (values[i] != o.values[i]) {
-					if (!Objects.equals(values[i], o.values[i])) {
+			int valuesLength = values.length;
+			int startIndex = (int) LAST_EQUALS_MISMATCH_INDEX.getOpaque();
+			if (startIndex >= valuesLength) {
+				startIndex = 0;
+			}
+
+			for (int i = 0; i < valuesLength; i++) {
+				int index = startIndex + i;
+				if (index >= valuesLength) {
+					index -= valuesLength;
+				}
+				if (values[index] != o.values[index]) {
+					if (!Objects.equals(values[index], o.values[index])) {
+						LAST_EQUALS_MISMATCH_INDEX.setOpaque(index);
 						return false;
 					}
 				}