Add support to purge rows from MSC2716 and other tables when purging a room (#13825)

`event_failed_pull_attempts` added in https://github.com/matrix-org/synapse/pull/13589

MSC2716 related tables added in:

 - https://github.com/matrix-org/synapse/pull/10245/files#diff-3d42dfb44d02f7de3aada105e0bdc1cc9dd7f953cbf0f36c5d0f50827bf0320aR1
    - Renamed in https://github.com/matrix-org/synapse/pull/10838/files#diff-2730bfbe9e688b55e46f9371aefe67dac2bd2b2b7d9d6b92774eea1fcfae156dR1
 - https://github.com/matrix-org/synapse/pull/10498/files#diff-c52bbfbb5921a3f6f023b24343668479d966fac164f13b7c39d2197ce3afa7a5R1

2 files changed, 24 insertions, 0 deletions

diff --git a/synapse/storage/schema/__init__.py b/synapse/storage/schema/__init__.py
index 68e055c664..f29424d17a 100644
--- a/synapse/storage/schema/__init__.py
+++ b/synapse/storage/schema/__init__.py
@@ -83,6 +83,8 @@ Changes in SCHEMA_VERSION = 73;
       event_push_summary, receipts_linearized, and receipts_graph.
     - Add table `event_failed_pull_attempts` to keep track when we fail to pull
       events over federation.
+    - Add indexes to various tables (`event_failed_pull_attempts`, `insertion_events`,
+      `batch_events`) to make it easy to delete all associated rows when purging a room.
 """
 
 
diff --git a/synapse/storage/schema/main/delta/73/02room_id_indexes_for_purging.sql b/synapse/storage/schema/main/delta/73/02room_id_indexes_for_purging.sql
new file mode 100644
index 0000000000..6d38bdd430
--- /dev/null
+++ b/synapse/storage/schema/main/delta/73/02room_id_indexes_for_purging.sql
@@ -0,0 +1,22 @@
+/* Copyright 2022 The Matrix.org Foundation C.I.C
+ *
+ * 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.
+ */
+
+-- Add index so we can easily purge all rows from a given `room_id`
+CREATE INDEX IF NOT EXISTS event_failed_pull_attempts_room_id ON event_failed_pull_attempts(room_id);
+
+-- MSC2716 related tables:
+-- Add indexes so we can easily purge all rows from a given `room_id`
+CREATE INDEX IF NOT EXISTS insertion_events_room_id ON insertion_events(room_id);
+CREATE INDEX IF NOT EXISTS batch_events_room_id ON batch_events(room_id);