Cache the result of a get_rooms_for_user query, to make user_rooms_intersect() much lighter in the read-common case

This commit is contained in:
Paul "LeoNerd" Evans 2015-02-11 16:04:08 +00:00
parent 7be0f6594e
commit 45b56609ae

View File

@ -35,6 +35,11 @@ RoomsForUser = namedtuple(
class RoomMemberStore(SQLBaseStore):
def __init__(self, *args, **kw):
super(RoomMemberStore, self).__init__(*args, **kw)
self._user_rooms_cache = {}
def _store_room_member_txn(self, txn, event):
"""Store a room member in the database.
"""
@ -98,6 +103,8 @@ class RoomMemberStore(SQLBaseStore):
txn.execute(sql, (event.room_id, domain))
self.invalidate_rooms_for_user(target_user_id)
@defer.inlineCallbacks
def get_room_member(self, user_id, room_id):
"""Retrieve the current state of a room member.
@ -240,23 +247,43 @@ class RoomMemberStore(SQLBaseStore):
results = self._parse_events_txn(txn, rows)
return results
# TODO(paul): Create a nice @cached decorator to do this
# @cached
# def get_foo(...)
# ...
# invalidate_foo = get_foo.invalidator
@defer.inlineCallbacks
def get_rooms_for_user(self, user_id):
# TODO(paul): put some performance counters in here so we can easily
# track what impact this cache is having
if user_id in self._user_rooms_cache:
defer.returnValue(self._user_rooms_cache[user_id])
rooms = yield self.get_rooms_for_user_where_membership_is(
user_id, membership_list=[Membership.JOIN],
)
self._user_rooms_cache[user_id] = rooms
defer.returnValue(rooms)
def invalidate_rooms_for_user(self, user_id):
if user_id in self._user_rooms_cache:
del self._user_rooms_cache[user_id]
@defer.inlineCallbacks
def user_rooms_intersect(self, user_id_list):
""" Checks whether all the users whose IDs are given in a list share a
room.
This is a "hot path" function that's called a lot, e.g. by presence for
generating the event stream.
generating the event stream. As such, it is implemented locally by
wrapping logic around heavily-cached database queries.
"""
if len(user_id_list) < 2:
defer.returnValue(True)
deferreds = [
self.get_rooms_for_user_where_membership_is(
u, membership_list=[Membership.JOIN],
)
for u in user_id_list
]
deferreds = [self.get_rooms_for_user(u) for u in user_id_list]
results = yield defer.DeferredList(deferreds)