Add cache to room stream

synapse/storage/receipts.py

@@ -16,6 +16,7 @@
 from ._base import SQLBaseStore
 from synapse.util.caches.descriptors import cachedInlineCallbacks, cachedList, cached
 from synapse.util.caches import cache_counter, caches_by_name
+from synapse.util.caches.room_change_cache import RoomStreamChangeCache
 
 from twisted.internet import defer
 
@@ -31,8 +32,8 @@ class ReceiptsStore(SQLBaseStore):
     def __init__(self, hs):
         super(ReceiptsStore, self).__init__(hs)
 
-        self._receipts_stream_cache = _RoomStreamChangeCache(
-            self._receipts_id_gen.get_max_token(None)
+        self._receipts_stream_cache = RoomStreamChangeCache(
+            "ReceiptsRoomChangeCache", self._receipts_id_gen.get_max_token(None)
         )
 
     @cached(num_args=2)
@@ -370,63 +371,3 @@ class ReceiptsStore(SQLBaseStore):
                 "data": json.dumps(data),
             }
         )
-
-
-class _RoomStreamChangeCache(object):
-    """Keeps track of the stream_id of the latest change in rooms.
-
-    Given a list of rooms and stream key, it will give a subset of rooms that
-    may have changed since that key. If the key is too old then the cache
-    will simply return all rooms.
-    """
-    def __init__(self, current_key, size_of_cache=10000):
-        self._size_of_cache = size_of_cache
-        self._room_to_key = {}
-        self._cache = sorteddict()
-        self._earliest_key = current_key
-        self.name = "ReceiptsRoomChangeCache"
-        caches_by_name[self.name] = self._cache
-
-    @defer.inlineCallbacks
-    def get_rooms_changed(self, store, room_ids, key):
-        """Returns subset of room ids that have had new receipts since the
-        given key. If the key is too old it will just return the given list.
-        """
-        if key > (yield self._get_earliest_key(store)):
-            keys = self._cache.keys()
-            i = keys.bisect_right(key)
-
-            result = set(
-                self._cache[k] for k in keys[i:]
-            ).intersection(room_ids)
-
-            cache_counter.inc_hits(self.name)
-        else:
-            result = room_ids
-            cache_counter.inc_misses(self.name)
-
-        defer.returnValue(result)
-
-    @defer.inlineCallbacks
-    def room_has_changed(self, store, room_id, key):
-        """Informs the cache that the room has been changed at the given key.
-        """
-        if key > (yield self._get_earliest_key(store)):
-            old_key = self._room_to_key.get(room_id, None)
-            if old_key:
-                key = max(key, old_key)
-                self._cache.pop(old_key, None)
-            self._cache[key] = room_id
-
-            while len(self._cache) > self._size_of_cache:
-                k, r = self._cache.popitem()
-                self._earliest_key = max(k, self._earliest_key)
-                self._room_to_key.pop(r, None)
-
-    @defer.inlineCallbacks
-    def _get_earliest_key(self, store):
-        if self._earliest_key is None:
-            self._earliest_key = yield store.get_max_receipt_stream_id()
-            self._earliest_key = int(self._earliest_key)
-
-        defer.returnValue(self._earliest_key)