diff --git a/synapse/storage/controllers/state.py b/synapse/storage/controllers/state.py
index bbe568bf05..b1aa17047c 100644
--- a/synapse/storage/controllers/state.py
+++ b/synapse/storage/controllers/state.py
@@ -23,6 +23,7 @@ from typing import (
List,
Mapping,
Optional,
+ Sequence,
Tuple,
)
@@ -524,12 +525,53 @@ class StateStorageController:
return state_map.get(key)
async def get_current_hosts_in_room(self, room_id: str) -> List[str]:
- """Get current hosts in room based on current state."""
+ """Get current hosts in room based on current state.
+
+ Blocks until we have full state for the given room. This only happens for rooms
+ with partial state.
+
+ Returns:
+ A list of hosts in the room, sorted by longest in the room first. (aka.
+ sorted by join with the lowest depth first).
+ """
await self._partial_state_room_tracker.await_full_state(room_id)
return await self.stores.main.get_current_hosts_in_room(room_id)
+ async def get_current_hosts_in_room_or_partial_state_approximation(
+ self, room_id: str
+ ) -> Sequence[str]:
+ """Get approximation of current hosts in room based on current state.
+
+ For rooms with full state, this is equivalent to `get_current_hosts_in_room`,
+ with the same order of results.
+
+ For rooms with partial state, no blocking occurs. Instead, the list of hosts
+ in the room at the time of joining is combined with the list of hosts which
+ joined the room afterwards. The returned list may include hosts that are not
+ actually in the room and exclude hosts that are in the room, since we may
+ calculate state incorrectly during the partial state phase. The order of results
+ is arbitrary for rooms with partial state.
+ """
+ # We have to read this list first to mitigate races with un-partial stating.
+ # This will be empty for rooms with full state.
+ hosts_at_join = await self.stores.main.get_partial_state_servers_at_join(
+ room_id
+ )
+
+ hosts_from_state = await self.stores.main.get_current_hosts_in_room(room_id)
+ hosts_from_state_set = set(hosts_from_state)
+
+ # First take the list of hosts based on the current state.
+ # For rooms with partial state, this will be missing most hosts.
+ hosts = list(hosts_from_state)
+ # Then add in the list of hosts in the room at the time we joined.
+ # This will be an empty list for rooms with full state.
+ hosts.extend(host for host in hosts_at_join if host not in hosts_from_state_set)
+
+ return hosts
+
async def get_users_in_room_with_profiles(
self, room_id: str
) -> Dict[str, ProfileInfo]:
|
