only check if settings need to change or mappings need to be checked if the index metadata has actually changed

src/main/java/org/elasticsearch/cluster/ClusterChangedEvent.java

@@ -21,6 +21,8 @@ package org.elasticsearch.cluster;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;
+import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
 
 import java.util.List;
@@ -122,6 +124,20 @@ public class ClusterChangedEvent {
         return state.metaData() != previousState.metaData();
     }
 
+    public boolean indexMetaDataChanged(IndexMetaData current) {
+        MetaData previousMetaData = previousState.metaData();
+        if (previousMetaData == null) {
+            return true;
+        }
+        IndexMetaData previousIndexMetaData = previousMetaData.index(current.index());
+        // no need to check on version, since disco modules will make sure to use the
+        // same instance if its a version match
+        if (previousIndexMetaData == current) {
+            return false;
+        }
+        return false;
+    }
+
     public boolean blocksChanged() {
         return state.blocks() != previousState.blocks();
     }

src/main/java/org/elasticsearch/indices/cluster/IndicesClusterStateService.java

@@ -304,11 +304,18 @@ public class IndicesClusterStateService extends AbstractLifecycleComponent<Indic
     }
 
     private void applySettings(ClusterChangedEvent event) {
+        if (!event.metaDataChanged()) {
+            return;
+        }
         for (IndexMetaData indexMetaData : event.state().metaData()) {
             if (!indicesService.hasIndex(indexMetaData.index())) {
                 // we only create / update here
                 continue;
             }
+            // if the index meta data didn't change, no need check for refreshed settings
+            if (!event.indexMetaDataChanged(indexMetaData)) {
+                continue;
+            }
             String index = indexMetaData.index();
             IndexService indexService = indicesService.indexServiceSafe(index);
             IndexSettingsService indexSettingsService = indexService.injector().getInstance(IndexSettingsService.class);
@@ -324,6 +331,10 @@ public class IndicesClusterStateService extends AbstractLifecycleComponent<Indic
                 // we only create / update here
                 continue;
             }
+            // if the index meta data didn't change, no need check for refreshed settings
+            if (!event.indexMetaDataChanged(indexMetaData)) {
+                continue;
+            }
             List<String> typesToRefresh = null;
             String index = indexMetaData.index();
             IndexService indexService = indicesService.indexServiceSafe(index);