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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.
This commit is contained in:
Erik Johnston 2022-07-25 10:21:06 +01:00 committed by GitHub
parent 357561c1a2
commit 43adf2521c
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4 changed files with 109 additions and 91 deletions
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1
changelog.d/13313.misc Normal file
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@ -0,0 +1 @@
Change `get_users_in_room` and `get_rooms_for_user` caches to enable pruning of old entries.

112
synapse/handlers/presence.py
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@ -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],

4
synapse/storage/_base.py
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@ -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)

83
synapse/storage/databases/main/roommember.py
View File

@ -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