just user dir?

synapse/storage/schema/full_schemas/54/stream_positions.sql

@@ -4,4 +4,22 @@ INSERT INTO federation_stream_position (type, stream_id) VALUES ('federation', -
 INSERT INTO federation_stream_position (type, stream_id) SELECT 'events', coalesce(max(stream_ordering), -1) FROM events;
 INSERT INTO user_directory_stream_pos (stream_id) VALUES (null);
 INSERT INTO stats_stream_pos (stream_id) VALUES (null);
-INSERT INTO event_push_summary_stream_ordering (stream_ordering) VALUES (0);
+INSERT INTO event_push_summary_stream_ordering (stream_ordering) VALUES (0);
+
+--- User dir population
+
+-- Set up staging tables
+INSERT INTO background_updates (update_name, progress_json) VALUES
+    ('populate_user_directory_createtables', '{}');
+
+-- Run through each room and update the user directory according to who is in it
+INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
+    ('populate_user_directory_process_rooms', '{}', 'populate_user_directory_createtables');
+
+-- Insert all users, if search_all_users is on
+INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
+    ('populate_user_directory_process_users', '{}', 'populate_user_directory_process_rooms');
+
+-- Clean up staging tables
+INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
+    ('populate_user_directory_cleanup', '{}', 'populate_user_directory_process_users');