diff --git a/synapse/storage/databases/main/events_worker.py b/synapse/storage/databases/main/events_worker.py

index c342df2a8b..6e7f16f39c 100644
--- a/synapse/storage/databases/main/events_worker.py
+++ b/synapse/storage/databases/main/events_worker.py
@@ -33,7 +33,10 @@ from synapse.api.room_versions import (
 from synapse.events import EventBase, make_event_from_dict
 from synapse.events.utils import prune_event
 from synapse.logging.context import PreserveLoggingContext, current_context
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import (
+    run_as_background_process,
+    wrap_as_background_process,
+)
 from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
 from synapse.replication.tcp.streams import BackfillStream
 from synapse.replication.tcp.streams.events import EventsStream
@@ -140,10 +143,7 @@ class EventsWorkerStore(SQLBaseStore):
         if hs.config.run_background_tasks:
             # We periodically clean out old transaction ID mappings
             self._clock.looping_call(
-                run_as_background_process,
-                5 * 60 * 1000,
-                "_cleanup_old_transaction_ids",
-                self._cleanup_old_transaction_ids,
+                self._cleanup_old_transaction_ids, 5 * 60 * 1000,
             )
 
         self._get_event_cache = LruCache(
@@ -1374,6 +1374,7 @@ class EventsWorkerStore(SQLBaseStore):
 
         return mapping
 
+    @wrap_as_background_process("_cleanup_old_transaction_ids")
     async def _cleanup_old_transaction_ids(self):
         """Cleans out transaction id mappings older than 24hrs.
         """