try and make loading items from the cache faster

1 files changed, 4 insertions, 2 deletions

diff --git a/synapse/util/caches/stream_change_cache.py b/synapse/util/caches/stream_change_cache.py

index 817118e30f..c81518c6bc 100644
--- a/synapse/util/caches/stream_change_cache.py
+++ b/synapse/util/caches/stream_change_cache.py
@@ -78,7 +78,8 @@ class StreamChangeCache(object):
             not_known_entities = set(entities) - set(self._entity_to_key)
 
             result = (
-                set(self._cache.values()[self._cache.bisect_right(stream_pos) :])
+                {self._cache[k] for k in in self._cache.islice(
+                    start=self._cache.bisect_right(stream_pos))}
                 .intersection(entities)
                 .union(not_known_entities)
             )
@@ -113,7 +114,8 @@ class StreamChangeCache(object):
         assert type(stream_pos) is int
 
         if stream_pos >= self._earliest_known_stream_pos:
-            return self._cache.values()[self._cache.bisect_right(stream_pos) :]
+            return {self._cache[k] for k in in self._cache.islice(
+                start=self._cache.bisect_right(stream_pos))}
         else:
             return None