remove null constraint on user_dir.room_id

synapse/storage/schema/delta/46/user_dir_null_room_ids.sql

+/* Copyright 2017 New Vector 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.
+ */
+
+-- change the user_directory table to also cover global local user profiles
+-- rather than just profiles within specific rooms.
+
+CREATE TABLE user_directory2 (
+    user_id TEXT NOT NULL,
+    room_id TEXT,
+    display_name TEXT,
+    avatar_url TEXT
+);
+
+INSERT INTO user_directory2(user_id, room_id, display_name, avatar_url)
+    SELECT user_id, room_id, display_name, avatar_url from user_directory;
+
+DROP TABLE user_directory;
+ALTER TABLE user_directory2 RENAME TO user_directory;
+
+-- create indexes after doing the inserts because that's more efficient.
+-- it also means we can give it the same name as the old one without renaming.
+CREATE INDEX user_directory_room_idx ON user_directory(room_id);
+CREATE UNIQUE INDEX user_directory_user_idx ON user_directory(user_id);