diff options
Diffstat (limited to 'synapse/storage/databases/main/roommember.py')
| -rw-r--r-- | synapse/storage/databases/main/roommember.py | 88 |
1 files changed, 71 insertions, 17 deletions
diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py index 9e5034b401..06500457bd 100644 --- a/synapse/storage/databases/main/roommember.py +++ b/synapse/storage/databases/main/roommember.py @@ -187,27 +187,48 @@ class RoomMemberWorkerStore(EventsWorkerStore): @cached(max_entries=100000, iterable=True) async def get_users_in_room(self, room_id: str) -> List[str]: + """ + Returns a list of users in the room sorted by longest in the room first + (aka. with the lowest depth). This is done to match the sort in + `get_current_hosts_in_room()` and so we can re-use the cache but it's + not horrible to have here either. + """ + return await self.db_pool.runInteraction( "get_users_in_room", self.get_users_in_room_txn, room_id ) def get_users_in_room_txn(self, txn: LoggingTransaction, room_id: str) -> List[str]: + """ + Returns a list of users in the room sorted by longest in the room first + (aka. with the lowest depth). This is done to match the sort in + `get_current_hosts_in_room()` and so we can re-use the cache but it's + not horrible to have here either. + """ # If we can assume current_state_events.membership is up to date # then we can avoid a join, which is a Very Good Thing given how # frequently this function gets called. if self._current_state_events_membership_up_to_date: sql = """ - SELECT state_key FROM current_state_events - WHERE type = 'm.room.member' AND room_id = ? AND membership = ? + SELECT c.state_key FROM current_state_events as c + /* Get the depth of the event from the events table */ + INNER JOIN events AS e USING (event_id) + WHERE c.type = 'm.room.member' AND c.room_id = ? AND membership = ? + /* Sorted by lowest depth first */ + ORDER BY e.depth ASC; """ else: sql = """ - SELECT state_key FROM room_memberships as m + SELECT c.state_key FROM room_memberships as m + /* Get the depth of the event from the events table */ + INNER JOIN events AS e USING (event_id) INNER JOIN current_state_events as c ON m.event_id = c.event_id AND m.room_id = c.room_id AND m.user_id = c.state_key WHERE c.type = 'm.room.member' AND c.room_id = ? AND m.membership = ? + /* Sorted by lowest depth first */ + ORDER BY e.depth ASC; """ txn.execute(sql, (room_id, Membership.JOIN)) @@ -1037,37 +1058,70 @@ class RoomMemberWorkerStore(EventsWorkerStore): return True @cached(iterable=True, max_entries=10000) - async def get_current_hosts_in_room(self, room_id: str) -> Set[str]: - """Get current hosts in room based on current state.""" + async def get_current_hosts_in_room(self, room_id: str) -> List[str]: + """ + Get current hosts in room based on current state. + + The heuristic of sorting by servers who have been in the room the + longest is good because they're most likely to have anything we ask + about. + + Returns: + Returns a list of servers sorted by longest in the room first. (aka. + sorted by join with the lowest depth first). + """ # First we check if we already have `get_users_in_room` in the cache, as # we can just calculate result from that users = self.get_users_in_room.cache.get_immediate( (room_id,), None, update_metrics=False ) - if users is not None: - return {get_domain_from_id(u) for u in users} - - if isinstance(self.database_engine, Sqlite3Engine): + if users is None and isinstance(self.database_engine, Sqlite3Engine): # If we're using SQLite then let's just always use # `get_users_in_room` rather than funky SQL. users = await self.get_users_in_room(room_id) - return {get_domain_from_id(u) for u in users} + + if users is not None: + # Because `users` is sorted from lowest -> highest depth, the list + # of domains will also be sorted that way. + domains: List[str] = [] + # We use a `Set` just for fast lookups + domain_set: Set[str] = set() + for u in users: + domain = get_domain_from_id(u) + if domain not in domain_set: + domain_set.add(domain) + domains.append(domain) + return domains # For PostgreSQL we can use a regex to pull out the domains from the # joined users in `current_state_events` via regex. - def get_current_hosts_in_room_txn(txn: LoggingTransaction) -> Set[str]: + def get_current_hosts_in_room_txn(txn: LoggingTransaction) -> List[str]: + # Returns a list of servers currently joined in the room sorted by + # longest in the room first (aka. with the lowest depth). The + # heuristic of sorting by servers who have been in the room the + # longest is good because they're most likely to have anything we + # ask about. sql = """ - SELECT DISTINCT substring(state_key FROM '@[^:]*:(.*)$') - FROM current_state_events + SELECT + /* Match the domain part of the MXID */ + substring(c.state_key FROM '@[^:]*:(.*)$') as server_domain + FROM current_state_events c + /* Get the depth of the event from the events table */ + INNER JOIN events AS e USING (event_id) WHERE - type = 'm.room.member' - AND membership = 'join' - AND room_id = ? + /* Find any join state events in the room */ + c.type = 'm.room.member' + AND c.membership = 'join' + AND c.room_id = ? + /* Group all state events from the same domain into their own buckets (groups) */ + GROUP BY server_domain + /* Sorted by lowest depth first */ + ORDER BY min(e.depth) ASC; """ txn.execute(sql, (room_id,)) - return {d for d, in txn} + return [d for d, in txn] return await self.db_pool.runInteraction( "get_current_hosts_in_room", get_current_hosts_in_room_txn |