2 files changed, 5 insertions, 1 deletions
diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py
index 04b6abdc24..581dffd8a0 100644
--- a/synapse/util/async_helpers.py
+++ b/synapse/util/async_helpers.py
@@ -73,6 +73,10 @@ class ObservableDeferred(object):
         def errback(f):
             object.__setattr__(self, "_result", (False, f))
             while self._observers:
+                # This is a little bit of magic to correctly propagate stack
+                # traces when we `await` on one of the observer deferreds.
+                f.value.__failure__ = f
+
                 try:
                     # TODO: Handle errors here.
                     self._observers.pop().errback(f)
diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py
index 82d3eefe0e..b68f9fe0d4 100644
--- a/synapse/util/caches/response_cache.py
+++ b/synapse/util/caches/response_cache.py
@@ -144,7 +144,7 @@ class ResponseCache(object):
         """
         result = self.get(key)
         if not result:
-            logger.info(
+            logger.debug(
                 "[%s]: no cached result for [%s], calculating new one", self._name, key
             )
             d = run_in_background(callback, *args, **kwargs)