Wait for lazy join to complete when getting current state (#12872)

4 files changed, 33 insertions, 31 deletions

diff --git a/synapse/storage/databases/main/room.py b/synapse/storage/databases/main/room.py
index cfd8ce1624..68d4fc2e64 100644
--- a/synapse/storage/databases/main/room.py
+++ b/synapse/storage/databases/main/room.py
@@ -1139,6 +1139,24 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
             keyvalues={"room_id": room_id},
         )
 
+    async def is_partial_state_room(self, room_id: str) -> bool:
+        """Checks if this room has partial state.
+
+        Returns true if this is a "partial-state" room, which means that the state
+        at events in the room, and `current_state_events`, may not yet be
+        complete.
+        """
+
+        entry = await self.db_pool.simple_select_one_onecol(
+            table="partial_state_rooms",
+            keyvalues={"room_id": room_id},
+            retcol="room_id",
+            allow_none=True,
+            desc="is_partial_state_room",
+        )
+
+        return entry is not None
+
 
 class _BackgroundUpdates:
     REMOVE_TOMESTONED_ROOMS_BG_UPDATE = "remove_tombstoned_rooms_from_directory"
diff --git a/synapse/storage/databases/main/state.py b/synapse/storage/databases/main/state.py
index 3f2be3854b..bdd00273cd 100644
--- a/synapse/storage/databases/main/state.py
+++ b/synapse/storage/databases/main/state.py
@@ -242,7 +242,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         Raises:
             NotFoundError if the room is unknown
         """
-        state_ids = await self.get_current_state_ids(room_id)
+        state_ids = await self.get_partial_current_state_ids(room_id)
 
         if not state_ids:
             raise NotFoundError(f"Current state for room {room_id} is empty")
@@ -258,10 +258,12 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         return create_event
 
     @cached(max_entries=100000, iterable=True)
-    async def get_current_state_ids(self, room_id: str) -> StateMap[str]:
+    async def get_partial_current_state_ids(self, room_id: str) -> StateMap[str]:
         """Get the current state event ids for a room based on the
         current_state_events table.
 
+        This may be the partial state if we're lazy joining the room.
+
         Args:
             room_id: The room to get the state IDs of.
 
@@ -280,17 +282,19 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             return {(intern_string(r[0]), intern_string(r[1])): r[2] for r in txn}
 
         return await self.db_pool.runInteraction(
-            "get_current_state_ids", _get_current_state_ids_txn
+            "get_partial_current_state_ids", _get_current_state_ids_txn
         )
 
     # FIXME: how should this be cached?
-    async def get_filtered_current_state_ids(
+    async def get_partial_filtered_current_state_ids(
         self, room_id: str, state_filter: Optional[StateFilter] = None
     ) -> StateMap[str]:
         """Get the current state event of a given type for a room based on the
         current_state_events table.  This may not be as up-to-date as the result
         of doing a fresh state resolution as per state_handler.get_current_state
 
+        This may be the partial state if we're lazy joining the room.
+
         Args:
             room_id
             state_filter: The state filter used to fetch state
@@ -306,7 +310,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
 
         if not where_clause:
             # We delegate to the cached version
-            return await self.get_current_state_ids(room_id)
+            return await self.get_partial_current_state_ids(room_id)
 
         def _get_filtered_current_state_ids_txn(
             txn: LoggingTransaction,
@@ -334,30 +338,6 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             "get_filtered_current_state_ids", _get_filtered_current_state_ids_txn
         )
 
-    async def get_canonical_alias_for_room(self, room_id: str) -> Optional[str]:
-        """Get canonical alias for room, if any
-
-        Args:
-            room_id: The room ID
-
-        Returns:
-            The canonical alias, if any
-        """
-
-        state = await self.get_filtered_current_state_ids(
-            room_id, StateFilter.from_types([(EventTypes.CanonicalAlias, "")])
-        )
-
-        event_id = state.get((EventTypes.CanonicalAlias, ""))
-        if not event_id:
-            return None
-
-        event = await self.get_event(event_id, allow_none=True)
-        if not event:
-            return None
-
-        return event.content.get("canonical_alias")
-
     @cached(max_entries=50000)
     async def _get_state_group_for_event(self, event_id: str) -> Optional[int]:
         return await self.db_pool.simple_select_one_onecol(
diff --git a/synapse/storage/databases/main/state_deltas.py b/synapse/storage/databases/main/state_deltas.py
index 188afec332..445213e12a 100644
--- a/synapse/storage/databases/main/state_deltas.py
+++ b/synapse/storage/databases/main/state_deltas.py
@@ -27,7 +27,7 @@ class StateDeltasStore(SQLBaseStore):
     # attribute. TODO: can we get static analysis to enforce this?
     _curr_state_delta_stream_cache: StreamChangeCache
 
-    async def get_current_state_deltas(
+    async def get_partial_current_state_deltas(
         self, prev_stream_id: int, max_stream_id: int
     ) -> Tuple[int, List[Dict[str, Any]]]:
         """Fetch a list of room state changes since the given stream id
@@ -42,6 +42,8 @@ class StateDeltasStore(SQLBaseStore):
             - prev_event_id (str|None): previous event_id for this state key. None
                 if it's new state.
 
+        This may be the partial state if we're lazy joining the room.
+
         Args:
             prev_stream_id: point to get changes since (exclusive)
             max_stream_id: the point that we know has been correctly persisted
diff --git a/synapse/storage/databases/main/user_directory.py b/synapse/storage/databases/main/user_directory.py
index 2282242e9d..ddb25b5cea 100644
--- a/synapse/storage/databases/main/user_directory.py
+++ b/synapse/storage/databases/main/user_directory.py
@@ -441,7 +441,9 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
             (EventTypes.RoomHistoryVisibility, ""),
         )
 
-        current_state_ids = await self.get_filtered_current_state_ids(  # type: ignore[attr-defined]
+        # Getting the partial state is fine, as we're not looking at membership
+        # events.
+        current_state_ids = await self.get_partial_filtered_current_state_ids(  # type: ignore[attr-defined]
             room_id, StateFilter.from_types(types_to_filter)
         )