Track device list updates per room.

synapse/storage/databases/main/devices.py

@@ -1680,6 +1680,7 @@ def _add_device_outbound_room_poke_txn(
  "room_id",
  "user_id",
  "device_id",
+ "converted_to_destinations",
  "opentracing_context",
  ),
  values=[
@@ -1688,6 +1689,7 @@ def _add_device_outbound_room_poke_txn(
  room_id,
  user_id,
  device_id,
+ True, # As we're updating `device_lists_outbound_pokes` at the same time.
  json_encoder.encode(context),
  )
  for room_id in room_ids

synapse/storage/schema/main/delta/69/01device_list_oubound_by_room.sql

@@ -18,7 +18,11 @@ CREATE TABLE device_lists_changes_in_room (
  room_id TEXT NOT NULL,
  user_id TEXT NOT NULL,
  device_id TEXT NOT NULL,
+ -- We track if we've calculated the hosts in the room and updated
+ -- `device_lists_outbound_pokes`.
+ converted_to_destinations BOOLEAN NOT NULL,
  opentracing_context TEXT
 );
 
 CREATE UNIQUE INDEX device_lists_changes_in_stream_id ON device_lists_changes_in_room(stream_id);
+CREATE INDEX device_lists_changes_in_stream_id_converted ON device_lists_changes_in_room(stream_id) WHERE NOT converted_to_destinations;