Fetch fewer events when getting hosts in room (#14962)

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David Robertson 2023-02-02 16:49:14 +00:00 committed by GitHub
parent f398886ab8
commit 2186ebed6c
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2 changed files with 45 additions and 2 deletions

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@ -0,0 +1 @@
Improve performance when joining or sending an event large rooms.

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@ -13,6 +13,7 @@
# See the License for the specific language governing permissions and # See the License for the specific language governing permissions and
# limitations under the License. # limitations under the License.
import logging import logging
from itertools import chain
from typing import ( from typing import (
TYPE_CHECKING, TYPE_CHECKING,
AbstractSet, AbstractSet,
@ -1131,12 +1132,33 @@ class RoomMemberWorkerStore(EventsWorkerStore):
else: else:
# The cache doesn't match the state group or prev state group, # The cache doesn't match the state group or prev state group,
# so we calculate the result from first principles. # so we calculate the result from first principles.
#
# We need to fetch all hosts joined to the room according to `state` by
# inspecting all join memberships in `state`. However, if the `state` is
# relatively recent then many of its events are likely to be held in
# the current state of the room, which is easily available and likely
# cached.
#
# We therefore compute the set of `state` events not in the
# current state and only fetch those.
current_memberships = (
await self._get_approximate_current_memberships_in_room(room_id)
)
unknown_state_events = {}
joined_users_in_current_state = []
for (type, state_key), event_id in state.items():
if event_id not in current_memberships:
unknown_state_events[type, state_key] = event_id
elif current_memberships[event_id] == Membership.JOIN:
joined_users_in_current_state.append(state_key)
joined_user_ids = await self.get_joined_user_ids_from_state( joined_user_ids = await self.get_joined_user_ids_from_state(
room_id, state room_id, unknown_state_events
) )
cache.hosts_to_joined_users = {} cache.hosts_to_joined_users = {}
for user_id in joined_user_ids: for user_id in chain(joined_user_ids, joined_users_in_current_state):
host = intern_string(get_domain_from_id(user_id)) host = intern_string(get_domain_from_id(user_id))
cache.hosts_to_joined_users.setdefault(host, set()).add(user_id) cache.hosts_to_joined_users.setdefault(host, set()).add(user_id)
@ -1147,6 +1169,26 @@ class RoomMemberWorkerStore(EventsWorkerStore):
return frozenset(cache.hosts_to_joined_users) return frozenset(cache.hosts_to_joined_users)
async def _get_approximate_current_memberships_in_room(
self, room_id: str
) -> Mapping[str, Optional[str]]:
"""Build a map from event id to membership, for all events in the current state.
The event ids of non-memberships events (e.g. `m.room.power_levels`) are present
in the result, mapped to values of `None`.
The result is approximate for partially-joined rooms. It is fully accurate
for fully-joined rooms.
"""
rows = await self.db_pool.simple_select_list(
"current_state_events",
keyvalues={"room_id": room_id},
retcols=("event_id", "membership"),
desc="has_completed_background_updates",
)
return {row["event_id"]: row["membership"] for row in rows}
@cached(max_entries=10000) @cached(max_entries=10000)
def _get_joined_hosts_cache(self, room_id: str) -> "_JoinedHostsCache": def _get_joined_hosts_cache(self, room_id: str) -> "_JoinedHostsCache":
return _JoinedHostsCache() return _JoinedHostsCache()