diff --git a/server/src/main/java/org/elasticsearch/index/mapper/MapperService.java b/server/src/main/java/org/elasticsearch/index/mapper/MapperService.java
index 7663ec817a0db..6424e75eaf662 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/MapperService.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/MapperService.java
@@ -109,10 +109,11 @@ public enum MergeReason {
 
     //TODO this needs to be cleaned up: _timestamp and _ttl are not supported anymore, _field_names, _seq_no, _version and _source are
     //also missing, not sure if on purpose. See IndicesModule#getMetadataMappers
-    private static ObjectHashSet<String> META_FIELDS = ObjectHashSet.from(
-            "_id", "_type", "_routing", "_index",
-            "_size", "_timestamp", "_ttl", IgnoredFieldMapper.NAME
-    );
+    private static final String[] SORTED_META_FIELDS = new String[]{
+        "_id", IgnoredFieldMapper.NAME, "_index", "_routing", "_size", "_timestamp", "_ttl", "_type"
+    };
+
+    private static final ObjectHashSet<String> META_FIELDS = ObjectHashSet.from(SORTED_META_FIELDS);
 
     private static final DeprecationLogger deprecationLogger = new DeprecationLogger(LogManager.getLogger(MapperService.class));
 
@@ -762,7 +763,7 @@ public static boolean isMetadataField(String fieldName) {
     }
 
     public static String[] getAllMetaFields() {
-        return META_FIELDS.toArray(String.class);
+        return Arrays.copyOf(SORTED_META_FIELDS, SORTED_META_FIELDS.length);
     }
 
     /** An analyzer wrapper that can lookup fields within the index mappings */
@@ -789,5 +790,4 @@ protected Analyzer getWrappedAnalyzer(String fieldName) {
             return defaultAnalyzer;
         }
     }
-
 }