Don't reinsert into event_edges

synapse/storage/events.py

@@ -149,14 +149,6 @@ class EventsStore(SQLBaseStore):
                 event.depth
             )
 
-        self._handle_prev_events(
-            txn,
-            outlier=outlier,
-            event_id=event.event_id,
-            prev_events=event.prev_events,
-            room_id=event.room_id,
-        )
-
         have_persisted = self._simple_select_one_onecol_txn(
             txn,
             table="event_json",
@@ -196,6 +188,14 @@ class EventsStore(SQLBaseStore):
                 )
             return
 
+        self._handle_prev_events(
+            txn,
+            outlier=outlier,
+            event_id=event.event_id,
+            prev_events=event.prev_events,
+            room_id=event.room_id,
+        )
+
         if event.type == EventTypes.Member:
             self._store_room_member_txn(txn, event)
         elif event.type == EventTypes.Name: