Add get_users_with_read_receipts_in_room cache

1 files changed, 28 insertions, 0 deletions

diff --git a/synapse/storage/receipts.py b/synapse/storage/receipts.py
index fdcf28f3e1..964f30dff7 100644
--- a/synapse/storage/receipts.py
+++ b/synapse/storage/receipts.py
@@ -34,6 +34,26 @@ class ReceiptsStore(SQLBaseStore):
             "ReceiptsRoomChangeCache", self._receipts_id_gen.get_current_token()
         )
 
+    @cachedInlineCallbacks()
+    def get_users_with_read_receipts_in_room(self, room_id):
+        receipts = yield self.get_receipts_for_room(room_id, "m.read")
+        defer.returnValue(set(r['user_id'] for r in receipts))
+
+    def _invalidate_get_users_with_receipts_in_room(self, room_id, receipt_type,
+                                                    user_id):
+        if receipt_type != "m.read":
+            return
+
+        # Returns an ObservableDeferred
+        res = self.get_users_with_read_receipts_in_room.cache.get((room_id,), None)
+
+        if res and res.called and user_id in res.result:
+            # We'd only be adding to the set, so no point invalidating if the
+            # user is already there
+            return
+
+        self.get_users_with_read_receipts_in_room.invalidate((room_id,))
+
     @cached(num_args=2)
     def get_receipts_for_room(self, room_id, receipt_type):
         return self._simple_select_list(
@@ -229,6 +249,10 @@ class ReceiptsStore(SQLBaseStore):
             self.get_receipts_for_room.invalidate, (room_id, receipt_type)
         )
         txn.call_after(
+            self._invalidate_get_users_with_receipts_in_room,
+            room_id, receipt_type, user_id,
+        )
+        txn.call_after(
             self.get_receipts_for_user.invalidate, (user_id, receipt_type)
         )
         # FIXME: This shouldn't invalidate the whole cache
@@ -374,6 +398,10 @@ class ReceiptsStore(SQLBaseStore):
             self.get_receipts_for_room.invalidate, (room_id, receipt_type)
         )
         txn.call_after(
+            self._invalidate_get_users_with_receipts_in_room,
+            room_id, receipt_type, user_id,
+        )
+        txn.call_after(
             self.get_receipts_for_user.invalidate, (user_id, receipt_type)
         )
         # FIXME: This shouldn't invalidate the whole cache