ATLAS-2082: basic-search fails when in-memory filters all results from index-query

repository/src/main/java/org/apache/atlas/discovery/ClassificationSearchProcessor.java

@@ -236,6 +236,10 @@ public class ClassificationSearchProcessor extends SearchProcessor {
             // Now filter on the tag attributes
             Set<String> guids = getGuids(entityVertices);
 
+            // Clear prior results
+            entityVertices.clear();
+
+            if (CollectionUtils.isNotEmpty(guids)) {
                 gremlinQueryBindings.put("guids", guids);
 
                 try {
@@ -243,17 +247,14 @@ public class ClassificationSearchProcessor extends SearchProcessor {
                     ScriptEngine      gremlinScriptEngine = graph.getGremlinScriptEngine();
                     List<AtlasVertex> atlasVertices       = (List<AtlasVertex>) graph.executeGremlinScript(gremlinScriptEngine, gremlinQueryBindings, gremlinTagFilterQuery, false);
 
-                // Clear prior results
-                entityVertices.clear();
-
                     if (CollectionUtils.isNotEmpty(atlasVertices)) {
                         entityVertices.addAll(atlasVertices);
                     }
-
                 } catch (AtlasBaseException | ScriptException e) {
                     LOG.warn(e.getMessage(), e);
                 }
             }
+        }
 
         super.filter(entityVertices);
 

repository/src/main/java/org/apache/atlas/discovery/EntitySearchProcessor.java

@@ -173,13 +173,18 @@ public class EntitySearchProcessor extends SearchProcessor {
                     CollectionUtils.filter(entityVertices, inMemoryPredicate);
 
                     if (graphQuery != null) {
-                        AtlasGraphQuery guidQuery = context.getGraph().query().in(Constants.GUID_PROPERTY_KEY, getGuids(entityVertices));
+                        Set<String> guids = getGuids(entityVertices);
+
+                        entityVertices.clear();
+
+                        if (CollectionUtils.isNotEmpty(guids)) {
+                            AtlasGraphQuery guidQuery = context.getGraph().query().in(Constants.GUID_PROPERTY_KEY, guids);
 
                             guidQuery.addConditionsFrom(graphQuery);
 
-                        entityVertices.clear();
                             getVertices(guidQuery.vertices().iterator(), entityVertices);
                         }
+                    }
                 } else {
                     Iterator<AtlasVertex> queryResult = graphQuery.vertices(qryOffset, limit).iterator();
 
@@ -211,12 +216,17 @@ public class EntitySearchProcessor extends SearchProcessor {
             LOG.debug("==> EntitySearchProcessor.filter({})", entityVertices.size());
         }
 
-        AtlasGraphQuery query = context.getGraph().query().in(Constants.GUID_PROPERTY_KEY, getGuids(entityVertices));
+        Set<String> guids = getGuids(entityVertices);
+
+        entityVertices.clear();
+
+        if (CollectionUtils.isNotEmpty(guids)) {
+            AtlasGraphQuery query = context.getGraph().query().in(Constants.GUID_PROPERTY_KEY, guids);
 
             query.addConditionsFrom(filterGraphQuery);
 
-        entityVertices.clear();
             getVertices(query.vertices().iterator(), entityVertices);
+        }
 
         super.filter(entityVertices);