1 files changed, 4 insertions, 2 deletions
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 5e2b1c0456..39be782937 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -59,7 +59,7 @@ from synapse.events.validator import EventValidator
 from synapse.federation.federation_client import InvalidResponseError
 from synapse.http.servlet import assert_params_in_dict
 from synapse.logging.context import nested_logging_context
-from synapse.logging.tracing import trace
+from synapse.logging.tracing import set_attribute, trace
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.module_api import NOT_SPAM
 from synapse.replication.http.federation import (
@@ -319,10 +319,12 @@ class FederationHandler:
         # attempting to paginate before backfill reached the visible history.
 
         extremities_to_request: List[str] = []
-        for bp in sorted_backfill_points:
+        for i, bp in enumerate(sorted_backfill_points):
             if len(extremities_to_request) >= 5:
                 break
 
+            set_attribute("backfill_point" + str(i), str(bp))
+
             # For regular backwards extremities, we don't have the extremity events
             # themselves, so we need to actually check the events that reference them -
             # their "successor" events.