diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index c6ce65b4cce2bc64e734028333a90cd72fc19a7a..f154b1c8aea4b100959a9ae518b2f784d1b17a7c 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -54,7 +54,7 @@ logger = logging.getLogger(__name__)
 
 # Remember to update this number every time a change is made to database
 # schema files, so the users will be informed on server restarts.
-SCHEMA_VERSION = 21
+SCHEMA_VERSION = 22
 
 dir_path = os.path.abspath(os.path.dirname(__file__))
 
diff --git a/synapse/storage/schema/delta/22/receipts_index.sql b/synapse/storage/schema/delta/22/receipts_index.sql
new file mode 100644
index 0000000000000000000000000000000000000000..b182b2b6618902a2da7e1b75d4365f6f49c31247
--- /dev/null
+++ b/synapse/storage/schema/delta/22/receipts_index.sql
@@ -0,0 +1,18 @@
+/* Copyright 2015 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+CREATE INDEX receipts_linearized_room_stream ON receipts_linearized(
+    room_id, stream_id
+);