GH-3002 start measuring performance before we initialise the iterator…

… and add comment so we don't move it again by mistake

Signed-off-by: Håvard Ottestad <[email protected]>

core/sail/shacl/src/main/java/org/eclipse/rdf4j/sail/shacl/ShaclSailConnection.java

@@ -439,17 +439,21 @@ private ValidationReport performValidation(List<Shape> shapes, boolean validateE
 							planNode.receiveLogger(validationExecutionLogger);
 						}
 
+						// Important to start measuring time before we call .iterator() since the initialisation of the
+						// iterator will already do a lot of work if there is for instance a Sort in the pipeline
+						// because Sort (among others) will consume its parent iterator and sort the results on
+						// initialization!
+						long before = 0;
+						if (sail.isPerformanceLogging()) {
+							before = System.currentTimeMillis();
+						}
+
 						try (CloseableIteration<? extends ValidationTuple, SailException> iterator = planNode
 								.iterator()) {
 							if (GlobalValidationExecutionLogging.loggingEnabled) {
 								logger.info("Start execution of plan:\n{}\n", shapePlanNodeTuple.getShape().toString());
 							}
 
-							long before = 0;
-							if (sail.isPerformanceLogging()) {
-								before = System.currentTimeMillis();
-							}
-
 							ValidationResultIterator validationResults;
 							try {
 								validationResults = new ValidationResultIterator(iterator,