Merge main into develop

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

@@ -21,4 +21,16 @@ public interface IndexReportingIterator {
 
 	String getIndexName();
 
+	default long getSourceRowsScannedActual() {
+		return -1;
+	}
+
+	default long getSourceRowsMatchedActual() {
+		return -1;
+	}
+
+	default long getSourceRowsFilteredActual() {
+		return -1;
+	}
+
 }

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

@@ -8,6 +8,7 @@
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *******************************************************************************/
+// Some portions generated by Codex
 
 package org.eclipse.rdf4j.common.iteration;
 
@@ -16,12 +17,13 @@
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
+import java.util.function.ToLongFunction;
 
 /**
  * An Iteration that returns the bag union of the results of a number of Iterations. 'Bag union' means that the
  * UnionIteration does not filter duplicate objects.
  */
-public class UnionIteration<E> extends LookAheadIteration<E> {
+public class UnionIteration<E> extends LookAheadIteration<E> implements IndexReportingIterator {
 
 	/*-----------*
 	 * Variables *
@@ -31,6 +33,8 @@ public class UnionIteration<E> extends LookAheadIteration<E> {
 
 	private CloseableIteration<? extends E> currentIter;
 
+	private final List<IndexReportingIterator> indexReporters;
+
 	/*--------------*
 	 * Constructors *
 	 *--------------*/
@@ -51,7 +55,16 @@ public UnionIteration(CloseableIteration<? extends E>... args) {
 	 * @param args The Iterations containing the elements to iterate over.
 	 */
 	public UnionIteration(Iterable<? extends CloseableIteration<? extends E>> args) {
-		argIter = args.iterator();
+		List<CloseableIteration<? extends E>> iterations = new ArrayList<>();
+		List<IndexReportingIterator> reporters = new ArrayList<>();
+		for (CloseableIteration<? extends E> arg : args) {
+			iterations.add(arg);
+			if (arg instanceof IndexReportingIterator) {
+				reporters.add((IndexReportingIterator) arg);
+			}
+		}
+		argIter = iterations.iterator();
+		indexReporters = reporters;
 
 		// Initialize with empty iteration
 		currentIter = new EmptyIteration<>();
@@ -112,4 +125,43 @@ protected void handleClose() {
 		}
 
 	}
+
+	@Override
+	public String getIndexName() {
+		for (IndexReportingIterator indexReporter : indexReporters) {
+			String indexName = indexReporter.getIndexName();
+			if (indexName != null && !indexName.isEmpty()) {
+				return indexName;
+			}
+		}
+		return "";
+	}
+
+	@Override
+	public long getSourceRowsScannedActual() {
+		return aggregateMetric(IndexReportingIterator::getSourceRowsScannedActual);
+	}
+
+	@Override
+	public long getSourceRowsMatchedActual() {
+		return aggregateMetric(IndexReportingIterator::getSourceRowsMatchedActual);
+	}
+
+	@Override
+	public long getSourceRowsFilteredActual() {
+		return aggregateMetric(IndexReportingIterator::getSourceRowsFilteredActual);
+	}
+
+	private long aggregateMetric(ToLongFunction<IndexReportingIterator> metricSupplier) {
+		long total = 0L;
+		boolean found = false;
+		for (IndexReportingIterator indexReporter : indexReporters) {
+			long value = metricSupplier.applyAsLong(indexReporter);
+			if (value >= 0L) {
+				total += value;
+				found = true;
+			}
+		}
+		return found ? total : -1L;
+	}
 }

core/query/src/main/java/org/eclipse/rdf4j/query/Query.java

@@ -92,8 +92,9 @@ enum QueryType {
 	 *
 	 * @param level The explanation level that should be used to create the explanation. Choose between: Unoptimized (as
 	 *              parsed without optimizations) , Optimized (as is actually going to be used), Executed (as was
-	 *              executed/evaluated, including some real performance metrics), Timed (as was executed/evaluated
-	 *              including all real performance metrics). Executed and Timed level can potentially be slow.
+	 *              executed/evaluated with actual result sizes), Telemetry (as was executed/evaluated, including
+	 *              runtime telemetry metrics), Timed (as was executed/evaluated including timing for each plan node).
+	 *              Executed, Telemetry and Timed levels can potentially be slow.
 	 * @return The explanation that we generated, which can be viewed in a human readable format with toString(), as
 	 *         JSON or as a simplified query plan object structure.
 	 */

core/query/src/main/java/org/eclipse/rdf4j/query/explanation/Explanation.java

@@ -34,6 +34,7 @@ enum Level {
 		Unoptimized, // simple parsed
 		Optimized, // parsed and optimized, which includes cost estimated
 		Executed, // plan as it was executed, which includes resultSizeActual
+		Telemetry, // plan as it was executed with runtime telemetry metrics (without node timing)
 		Timed, // plan as it was executed, including resultSizeActual and where each node has been timed
 	}