Reduce size of joined_user cache

The _get_joined_users_from_context cache stores a mapping from user_id
to avatar_url and display_name. Instead of storing those in a dict,
store them in a namedtuple as that uses much less memory.

We also try converting the string to ascii to further reduce the size.

1 files changed, 5 insertions, 2 deletions

diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index 78b095c903..503fef4261 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -87,8 +87,11 @@ class BulkPushRuleEvaluator:
         condition_cache = {}
 
         for uid, rules in self.rules_by_user.items():
-            display_name = room_members.get(uid, {}).get("display_name", None)
-            if not display_name:
+            display_name = None
+            profile_info = room_members.get(uid, {})
+            if profile_info:
+                display_name = profile_info.display_name
+            else:
                 # Handle the case where we are pushing a membership event to
                 # that user, as they might not be already joined.
                 if event.type == EventTypes.Member and event.state_key == uid: