From d88e0ec0802b3b0a49853fb6b777a35b7c195ea6 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Tue, 4 Feb 2020 21:31:08 +0000
Subject: [PATCH] Database updates to populate rooms.room_version (#6847)

We're going to need this so that we can figure out how to handle redactions when fetching events from the database.
---
 changelog.d/6847.misc                         |  1 +
 .../57/rooms_version_column_2.sql.postgres    | 35 +++++++++++++++++++
 .../57/rooms_version_column_2.sql.sqlite      | 22 ++++++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 changelog.d/6847.misc
 create mode 100644 synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.postgres
 create mode 100644 synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.sqlite

diff --git a/changelog.d/6847.misc b/changelog.d/6847.misc
new file mode 100644
index 0000000000..094e911adb
--- /dev/null
+++ b/changelog.d/6847.misc
@@ -0,0 +1 @@
+Populate `rooms.room_version` database column at startup, rather than in a background update.
diff --git a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.postgres b/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.postgres
new file mode 100644
index 0000000000..c601cff6de
--- /dev/null
+++ b/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.postgres
@@ -0,0 +1,35 @@
+/* Copyright 2020 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.
+ */
+
+-- when we first added the room_version column, it was populated via a background
+-- update. We now need it to be populated before synapse starts, so we populate
+-- any remaining rows with a NULL room version now. For servers which have completed
+-- the background update, this will be pretty quick.
+
+-- the following query will set room_version to NULL if no create event is found for
+-- the room in current_state_events, and will set it to '1' if a create event with no
+-- room_version is found.
+
+UPDATE rooms SET room_version=(
+    SELECT COALESCE(json::json->'content'->>'room_version','1')
+    FROM current_state_events cse INNER JOIN event_json ej USING (event_id)
+    WHERE cse.room_id=rooms.room_id AND cse.type='m.room.create' AND cse.state_key=''
+) WHERE rooms.room_version IS NULL;
+
+-- we still allow the background update to complete: it has the useful side-effect of
+-- populating `rooms` with any missing rooms (based on the current_state_events table).
+
+-- see also rooms_version_column_2.sql.sqlite which has a copy of the above query, using
+-- sqlite syntax for the json extraction.
diff --git a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.sqlite b/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.sqlite
new file mode 100644
index 0000000000..335c6f2074
--- /dev/null
+++ b/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.sqlite
@@ -0,0 +1,22 @@
+/* Copyright 2020 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.
+ */
+
+-- see rooms_version_column_2.sql.postgres for details of what's going on here.
+
+UPDATE rooms SET room_version=(
+    SELECT COALESCE(json_extract(ej.json, '$.content.room_version'), '1')
+    FROM current_state_events cse INNER JOIN event_json ej USING (event_id)
+    WHERE cse.room_id=rooms.room_id AND cse.type='m.room.create' AND cse.state_key=''
+) WHERE rooms.room_version IS NULL;