Fix ElasticSearch scroll result is created even on no scroll CTR

Fixes #2038

Signed-off-by: Oleksandr Porunov <alexandr.porunov@gmail.com>

Author: porunov

janusgraph-backend-testutils/src/main/java/org/janusgraph/graphdb/JanusGraphBaseTest.java

@@ -453,13 +453,17 @@ public static <T> Stream<T> asStream(final Iterator<T> source) {
         return StreamSupport.stream(iterable.spliterator(),false);
     }
 
-    public JanusGraph getForceIndexGraph() throws BackendException {
-        final ModifiableConfiguration adjustedConfig = new ModifiableConfiguration(GraphDatabaseConfiguration.ROOT_NS, getConfiguration(), BasicConfiguration.Restriction.NONE);
+    public JanusGraph getForceIndexGraph() {
+        return getForceIndexGraph(getConfiguration());
+    }
+
+    public JanusGraph getForceIndexGraph(WriteConfiguration writeConfiguration) {
+        final ModifiableConfiguration adjustedConfig = new ModifiableConfiguration(GraphDatabaseConfiguration.ROOT_NS, writeConfiguration, BasicConfiguration.Restriction.NONE);
         adjustedConfig.set(GraphDatabaseConfiguration.FORCE_INDEX_USAGE, true);
-        final WriteConfiguration writeConfig = adjustedConfig.getConfiguration();
-        TestGraphConfigs.applyOverrides(writeConfig);
-        Preconditions.checkNotNull(writeConfig);
-        return JanusGraphFactory.open(writeConfig);
+        final WriteConfiguration adjustedWriteConfig = adjustedConfig.getConfiguration();
+        TestGraphConfigs.applyOverrides(adjustedWriteConfig);
+        Preconditions.checkNotNull(adjustedWriteConfig);
+        return JanusGraphFactory.open(adjustedWriteConfig);
     }
 
 }

janusgraph-backend-testutils/src/main/java/org/janusgraph/graphdb/JanusGraphIndexTest.java

@@ -2224,6 +2224,24 @@ public void testOrForceIndexPartialIndex() throws Exception {
         }
     }
 
+    @Test
+    public void testIndexDataRetrievalWithLimitLessThenBatch() throws Exception {
+        WriteConfiguration config = getConfiguration();
+        config.set("index.search.max-result-set-size", 10);
+        JanusGraph customGraph = getForceIndexGraph(config);
+        final JanusGraphManagement management = customGraph.openManagement();
+        final PropertyKey num = management.makePropertyKey("num").dataType(Integer.class).cardinality(Cardinality.SINGLE).make();
+        management.buildIndex("oridx", Vertex.class).addKey(num).buildMixedIndex(INDEX);
+        management.commit();
+        customGraph.tx().commit();
+        final GraphTraversalSource g = customGraph.traversal();
+        g.addV().property("num", 1).next();
+        g.addV().property("num", 2).next();
+        customGraph.tx().commit();
+        assertEquals(2, customGraph.traversal().V().has("num", P.lt(3)).limit(4).toList().size());
+        JanusGraphFactory.close(customGraph);
+    }
+
     @Test
     public void testOrForceIndexComposite() throws Exception {
         JanusGraph customGraph = null;

janusgraph-es/src/main/java/org/janusgraph/diskstorage/es/ElasticSearchIndex.java

@@ -1112,7 +1112,7 @@ public Stream<String> query(IndexQuery query, KeyInformation.IndexRetriever info
                 compat.createRequestBody(sr, useScroll? NULL_PARAMETERS : TRACK_TOTAL_HITS_DISABLED_PARAMETERS),
                 useScroll);
             log.debug("First Executed query [{}] in {} ms", query.getCondition(), response.getTook());
-            final ElasticSearchScroll resultIterator = new ElasticSearchScroll(client, response, sr.getSize());
+            final Iterator<RawQuery.Result<String>> resultIterator = getResultsIterator(useScroll, response, sr.getSize());
             final Stream<RawQuery.Result<String>> toReturn
                     = StreamSupport.stream(Spliterators.spliteratorUnknownSize(resultIterator, Spliterator.ORDERED), false);
             return (query.hasLimit() ? toReturn.limit(query.getLimit()) : toReturn).map(RawQuery.Result::getResult);
@@ -1121,6 +1121,10 @@ public Stream<String> query(IndexQuery query, KeyInformation.IndexRetriever info
         }
     }
 
+    private Iterator<RawQuery.Result<String>> getResultsIterator(boolean useScroll, ElasticSearchResponse response, int windowSize){
+        return (useScroll)? new ElasticSearchScroll(client, response, windowSize) : response.getResults().iterator();
+    }
+
     private String convertToEsDataType(Class<?> dataType, Mapping mapping) {
         if(String.class.isAssignableFrom(dataType)) {
             return "string";
@@ -1206,9 +1210,10 @@ private void addOrderToQuery(KeyInformation.IndexRetriever informations, Elastic
     public Stream<RawQuery.Result<String>> query(RawQuery query, KeyInformation.IndexRetriever information,
                                                  BaseTransaction tx) throws BackendException {
         final int size = query.hasLimit() ? Math.min(query.getLimit() + query.getOffset(), batchSize) : batchSize;
-        final ElasticSearchResponse response = runCommonQuery(query, information, tx, size, size >= batchSize );
+        final boolean useScroll = size >= batchSize;
+        final ElasticSearchResponse response = runCommonQuery(query, information, tx, size, useScroll);
         log.debug("First Executed query [{}] in {} ms", query.getQuery(), response.getTook());
-        final ElasticSearchScroll resultIterator = new ElasticSearchScroll(client, response, size);
+        final Iterator<RawQuery.Result<String>> resultIterator = getResultsIterator(useScroll, response, size);
         final Stream<RawQuery.Result<String>> toReturn
                 = StreamSupport.stream(Spliterators.spliteratorUnknownSize(resultIterator, Spliterator.ORDERED),
                 false).skip(query.getOffset());