From 43adf2521cc6952dcc7f0e3006dbfe52db85721a Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Mon, 25 Jul 2022 10:21:06 +0100 Subject: Refactor presence so we can prune user in room caches (#13313) See #10826 and #10786 for context as to why we had to disable pruning on those caches. Now that `get_users_who_share_room_with_user` is called frequently only for presence, we just need to make calls to it less frequent and then we can remove the various levels of caching that is going on. --- changelog.d/13313.misc | 1 + synapse/handlers/presence.py | 112 +++++++++------------------ synapse/storage/_base.py | 4 + synapse/storage/databases/main/roommember.py | 83 ++++++++++++++++---- 4 files changed, 109 insertions(+), 91 deletions(-) create mode 100644 changelog.d/13313.misc diff --git a/changelog.d/13313.misc b/changelog.d/13313.misc new file mode 100644 index 0000000000..0f3c1f0afd --- /dev/null +++ b/changelog.d/13313.misc @@ -0,0 +1 @@ +Change `get_users_in_room` and `get_rooms_for_user` caches to enable pruning of old entries. diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py index 895ea63ed3..741504ba9f 100644 --- a/synapse/handlers/presence.py +++ b/synapse/handlers/presence.py @@ -34,7 +34,6 @@ from typing import ( Callable, Collection, Dict, - FrozenSet, Generator, Iterable, List, @@ -42,7 +41,6 @@ from typing import ( Set, Tuple, Type, - Union, ) from prometheus_client import Counter @@ -68,7 +66,6 @@ from synapse.storage.databases.main import DataStore from synapse.streams import EventSource from synapse.types import JsonDict, StreamKeyType, UserID, get_domain_from_id from synapse.util.async_helpers import Linearizer -from synapse.util.caches.descriptors import _CacheContext, cached from synapse.util.metrics import Measure from synapse.util.wheel_timer import WheelTimer @@ -1656,15 +1653,18 @@ class PresenceEventSource(EventSource[int, UserPresenceState]): # doesn't return. C.f. #5503. return [], max_token - # Figure out which other users this user should receive updates for - users_interested_in = await self._get_interested_in(user, explicit_room_id) + # Figure out which other users this user should explicitly receive + # updates for + additional_users_interested_in = ( + await self.get_presence_router().get_interested_users(user.to_string()) + ) # We have a set of users that we're interested in the presence of. We want to # cross-reference that with the users that have actually changed their presence. # Check whether this user should see all user updates - if users_interested_in == PresenceRouter.ALL_USERS: + if additional_users_interested_in == PresenceRouter.ALL_USERS: # Provide presence state for all users presence_updates = await self._filter_all_presence_updates_for_user( user_id, include_offline, from_key @@ -1673,34 +1673,47 @@ class PresenceEventSource(EventSource[int, UserPresenceState]): return presence_updates, max_token # Make mypy happy. users_interested_in should now be a set - assert not isinstance(users_interested_in, str) + assert not isinstance(additional_users_interested_in, str) + + # We always care about our own presence. + additional_users_interested_in.add(user_id) + + if explicit_room_id: + user_ids = await self.store.get_users_in_room(explicit_room_id) + additional_users_interested_in.update(user_ids) # The set of users that we're interested in and that have had a presence update. # We'll actually pull the presence updates for these users at the end. - interested_and_updated_users: Union[Set[str], FrozenSet[str]] = set() + interested_and_updated_users: Collection[str] if from_key is not None: # First get all users that have had a presence update updated_users = stream_change_cache.get_all_entities_changed(from_key) # Cross-reference users we're interested in with those that have had updates. - # Use a slightly-optimised method for processing smaller sets of updates. - if updated_users is not None and len(updated_users) < 500: - # For small deltas, it's quicker to get all changes and then - # cross-reference with the users we're interested in + if updated_users is not None: + # If we have the full list of changes for presence we can + # simply check which ones share a room with the user. get_updates_counter.labels("stream").inc() - for other_user_id in updated_users: - if other_user_id in users_interested_in: - # mypy thinks this variable could be a FrozenSet as it's possibly set - # to one in the `get_entities_changed` call below, and `add()` is not - # method on a FrozenSet. That doesn't affect us here though, as - # `interested_and_updated_users` is clearly a set() above. - interested_and_updated_users.add(other_user_id) # type: ignore + + sharing_users = await self.store.do_users_share_a_room( + user_id, updated_users + ) + + interested_and_updated_users = ( + sharing_users.union(additional_users_interested_in) + ).intersection(updated_users) + else: # Too many possible updates. Find all users we can see and check # if any of them have changed. get_updates_counter.labels("full").inc() + users_interested_in = ( + await self.store.get_users_who_share_room_with_user(user_id) + ) + users_interested_in.update(additional_users_interested_in) + interested_and_updated_users = ( stream_change_cache.get_entities_changed( users_interested_in, from_key @@ -1709,7 +1722,10 @@ class PresenceEventSource(EventSource[int, UserPresenceState]): else: # No from_key has been specified. Return the presence for all users # this user is interested in - interested_and_updated_users = users_interested_in + interested_and_updated_users = ( + await self.store.get_users_who_share_room_with_user(user_id) + ) + interested_and_updated_users.update(additional_users_interested_in) # Retrieve the current presence state for each user users_to_state = await self.get_presence_handler().current_state_for_users( @@ -1804,62 +1820,6 @@ class PresenceEventSource(EventSource[int, UserPresenceState]): def get_current_key(self) -> int: return self.store.get_current_presence_token() - @cached(num_args=2, cache_context=True) - async def _get_interested_in( - self, - user: UserID, - explicit_room_id: Optional[str] = None, - cache_context: Optional[_CacheContext] = None, - ) -> Union[Set[str], str]: - """Returns the set of users that the given user should see presence - updates for. - - Args: - user: The user to retrieve presence updates for. - explicit_room_id: The users that are in the room will be returned. - - Returns: - A set of user IDs to return presence updates for, or "ALL" to return all - known updates. - """ - user_id = user.to_string() - users_interested_in = set() - users_interested_in.add(user_id) # So that we receive our own presence - - # cache_context isn't likely to ever be None due to the @cached decorator, - # but we can't have a non-optional argument after the optional argument - # explicit_room_id either. Assert cache_context is not None so we can use it - # without mypy complaining. - assert cache_context - - # Check with the presence router whether we should poll additional users for - # their presence information - additional_users = await self.get_presence_router().get_interested_users( - user.to_string() - ) - if additional_users == PresenceRouter.ALL_USERS: - # If the module requested that this user see the presence updates of *all* - # users, then simply return that instead of calculating what rooms this - # user shares - return PresenceRouter.ALL_USERS - - # Add the additional users from the router - users_interested_in.update(additional_users) - - # Find the users who share a room with this user - users_who_share_room = await self.store.get_users_who_share_room_with_user( - user_id, on_invalidate=cache_context.invalidate - ) - users_interested_in.update(users_who_share_room) - - if explicit_room_id: - user_ids = await self.store.get_users_in_room( - explicit_room_id, on_invalidate=cache_context.invalidate - ) - users_interested_in.update(user_ids) - - return users_interested_in - def handle_timeouts( user_states: List[UserPresenceState], diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py index a2f8310388..e30f9c76d4 100644 --- a/synapse/storage/_base.py +++ b/synapse/storage/_base.py @@ -80,6 +80,10 @@ class SQLBaseStore(metaclass=ABCMeta): ) self._attempt_to_invalidate_cache("get_local_users_in_room", (room_id,)) + # There's no easy way of invalidating this cache for just the users + # that have changed, so we just clear the entire thing. + self._attempt_to_invalidate_cache("does_pair_of_users_share_a_room", None) + for user_id in members_changed: self._attempt_to_invalidate_cache( "get_user_in_room_with_profile", (room_id, user_id) diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py index df6b82660e..e2cccc688c 100644 --- a/synapse/storage/databases/main/roommember.py +++ b/synapse/storage/databases/main/roommember.py @@ -21,6 +21,7 @@ from typing import ( FrozenSet, Iterable, List, + Mapping, Optional, Set, Tuple, @@ -55,6 +56,7 @@ from synapse.types import JsonDict, PersistedEventPosition, StateMap, get_domain from synapse.util.async_helpers import Linearizer from synapse.util.caches import intern_string from synapse.util.caches.descriptors import _CacheContext, cached, cachedList +from synapse.util.iterutils import batch_iter from synapse.util.metrics import Measure if TYPE_CHECKING: @@ -183,7 +185,7 @@ class RoomMemberWorkerStore(EventsWorkerStore): self._check_safe_current_state_events_membership_updated_txn, ) - @cached(max_entries=100000, iterable=True, prune_unread_entries=False) + @cached(max_entries=100000, iterable=True) async def get_users_in_room(self, room_id: str) -> List[str]: return await self.db_pool.runInteraction( "get_users_in_room", self.get_users_in_room_txn, room_id @@ -561,7 +563,7 @@ class RoomMemberWorkerStore(EventsWorkerStore): return results_dict.get("membership"), results_dict.get("event_id") - @cached(max_entries=500000, iterable=True, prune_unread_entries=False) + @cached(max_entries=500000, iterable=True) async def get_rooms_for_user_with_stream_ordering( self, user_id: str ) -> FrozenSet[GetRoomsForUserWithStreamOrdering]: @@ -732,25 +734,76 @@ class RoomMemberWorkerStore(EventsWorkerStore): ) return frozenset(r.room_id for r in rooms) - @cached( - max_entries=500000, - cache_context=True, - iterable=True, - prune_unread_entries=False, + @cached(max_entries=10000) + async def does_pair_of_users_share_a_room( + self, user_id: str, other_user_id: str + ) -> bool: + raise NotImplementedError() + + @cachedList( + cached_method_name="does_pair_of_users_share_a_room", list_name="other_user_ids" ) - async def get_users_who_share_room_with_user( - self, user_id: str, cache_context: _CacheContext + async def _do_users_share_a_room( + self, user_id: str, other_user_ids: Collection[str] + ) -> Mapping[str, Optional[bool]]: + """Return mapping from user ID to whether they share a room with the + given user. + + Note: `None` and `False` are equivalent and mean they don't share a + room. + """ + + def do_users_share_a_room_txn( + txn: LoggingTransaction, user_ids: Collection[str] + ) -> Dict[str, bool]: + clause, args = make_in_list_sql_clause( + self.database_engine, "state_key", user_ids + ) + + # This query works by fetching both the list of rooms for the target + # user and the set of other users, and then checking if there is any + # overlap. + sql = f""" + SELECT b.state_key + FROM ( + SELECT room_id FROM current_state_events + WHERE type = 'm.room.member' AND membership = 'join' AND state_key = ? + ) AS a + INNER JOIN ( + SELECT room_id, state_key FROM current_state_events + WHERE type = 'm.room.member' AND membership = 'join' AND {clause} + ) AS b using (room_id) + LIMIT 1 + """ + + txn.execute(sql, (user_id, *args)) + return {u: True for u, in txn} + + to_return = {} + for batch_user_ids in batch_iter(other_user_ids, 1000): + res = await self.db_pool.runInteraction( + "do_users_share_a_room", do_users_share_a_room_txn, batch_user_ids + ) + to_return.update(res) + + return to_return + + async def do_users_share_a_room( + self, user_id: str, other_user_ids: Collection[str] ) -> Set[str]: + """Return the set of users who share a room with the first users""" + + user_dict = await self._do_users_share_a_room(user_id, other_user_ids) + + return {u for u, share_room in user_dict.items() if share_room} + + async def get_users_who_share_room_with_user(self, user_id: str) -> Set[str]: """Returns the set of users who share a room with `user_id`""" - room_ids = await self.get_rooms_for_user( - user_id, on_invalidate=cache_context.invalidate - ) + room_ids = await self.get_rooms_for_user(user_id) user_who_share_room = set() for room_id in room_ids: - user_ids = await self.get_users_in_room( - room_id, on_invalidate=cache_context.invalidate - ) + user_ids = await self.get_users_in_room(room_id) user_who_share_room.update(user_ids) return user_who_share_room -- cgit 1.4.1