From dd871d54994eed29e1c8c8e7fcf943ee1cda2d22 Mon Sep 17 00:00:00 2001
From: Alan Paxton <alan.paxton@gmail.com>
Date: Tue, 19 Dec 2023 14:31:50 +0000
Subject: [PATCH] [optimize] save 1 sort of result sets

Where there is a single defined index, adding the first result (which is returned sorted) to a new result set causes an unnecessary extra sort() of the result set.
---
 .../java/org/exist/indexing/range/RangeIndexWorker.java  | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/extensions/indexes/range/src/main/java/org/exist/indexing/range/RangeIndexWorker.java b/extensions/indexes/range/src/main/java/org/exist/indexing/range/RangeIndexWorker.java
index 1f397c32407..c0c0374b4ab 100644
--- a/extensions/indexes/range/src/main/java/org/exist/indexing/range/RangeIndexWorker.java
+++ b/extensions/indexes/range/src/main/java/org/exist/indexing/range/RangeIndexWorker.java
@@ -518,7 +518,7 @@ private void write() {
     public NodeSet query(int contextId, DocumentSet docs, NodeSet contextSet, List<QName> qnames, AtomicValue[] keys, RangeIndex.Operator operator, int axis) throws IOException, XPathException {
         return index.withSearcher(searcher -> {
             List<QName> definedIndexes = getDefinedIndexes(qnames);
-            NodeSet resultSet = new NewArrayNodeSet();
+            NodeSet resultSet = null;
             for (QName qname : definedIndexes) {
                 Query query;
                 String field = LuceneUtil.encodeQName(qname, index.getBrokerPool().getSymbols());
@@ -534,7 +534,12 @@ public NodeSet query(int contextId, DocumentSet docs, NodeSet contextSet, List<Q
                 final short nodeType = qname.getNameType() == ElementValue.ATTRIBUTE ? Node.ATTRIBUTE_NODE : Node
                         .ELEMENT_NODE;
 
-                resultSet.addAll(doQuery(contextId, docs, contextSet, axis, searcher.searcher, nodeType, query, null));
+                final NodeSet indexedResultSet = doQuery(contextId, docs, contextSet, axis, searcher.searcher, nodeType, query, null);
+                if (resultSet == null) {
+                    resultSet = indexedResultSet;
+                } else {
+                    resultSet.addAll(indexedResultSet);
+                }
             }
             return resultSet;
         });