Improve the performance of calculating ignored users in large rooms (#9024)

This allows for efficiently finding which users ignore a particular
user.

Co-authored-by: Erik Johnston <erik@matrix.org>

1 files changed, 8 insertions, 4 deletions

diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index 10f27e4378..9018f9e20b 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -203,14 +203,18 @@ class BulkPushRuleEvaluator:
 
         condition_cache = {}  # type: Dict[str, bool]
 
+        # If the event is not a state event check if any users ignore the sender.
+        if not event.is_state():
+            ignorers = await self.store.ignored_by(event.sender)
+        else:
+            ignorers = set()
+
         for uid, rules in rules_by_user.items():
             if event.sender == uid:
                 continue
 
-            if not event.is_state():
-                is_ignored = await self.store.is_ignored_by(event.sender, uid)
-                if is_ignored:
-                    continue
+            if uid in ignorers:
+                continue
 
             display_name = None
             profile_info = room_members.get(uid)