Always process marker events regardless if backfilled

Before, we could rely on the `connected_insertion_event_query`
to navigate the and find the historical branch. But now
we solely rely on the marker event to point out the
historical branch. So we need to make sure to add
the insertion event extremeties whenever we see a marker event.
Whether it be a live event or backfilled.

synapse/handlers/federation.py

@@ -142,7 +142,7 @@ class FederationHandler:
         insertion_events_to_be_backfilled: Dict[str, int] = {}
         if self.hs.config.experimental.msc2716_enabled:
             insertion_events_to_be_backfilled = (
-                await self.store.get_insertion_event_backwards_extremities_in_room(
+                await self.store.get_insertion_event_backward_extremities_in_room(
                     room_id
                 )
             )
@@ -1055,8 +1055,8 @@ class FederationHandler:
         limit = min(limit, 100)
 
         events = await self.store.get_backfill_events(room_id, pdu_list, limit)
-        logger.info(
-            "old implementation backfill events=%s",
+        logger.debug(
+            "on_backfill_request: backfill events=%s",
             [
                 "event_id=%s,depth=%d,body=%s,prevs=%s\n"
                 % (

synapse/handlers/federation_event.py

@@ -752,9 +752,9 @@ class FederationEventHandler:
             backfilled: True if this is part of a historical batch of events (inhibits
                 notification to clients, and validation of device keys.)
         """
-
-        logger.info(
-            "backfill events=%s",
+        logger.debug(
+            "processing pulled backfilled=%s events=%s",
+            backfilled,
             [
                 "event_id=%s,depth=%d,body=%s,prevs=%s\n"
                 % (
@@ -1146,6 +1146,8 @@ class FederationEventHandler:
 
         await self._run_push_actions_and_persist_event(event, context, backfilled)
 
+        await self._handle_marker_event(origin, event)
+
         if backfilled:
             return
 
@@ -1223,8 +1225,6 @@ class FederationEventHandler:
                     event.sender,
                 )
 
-        await self._handle_marker_event(origin, event)
-
     async def _resync_device(self, sender: str) -> None:
         """We have detected that the device list for the given user may be out
         of sync, so we try and resync them.

synapse/storage/databases/main/event_federation.py

@@ -735,7 +735,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
             room_id,
         )
 
-    async def get_insertion_event_backwards_extremities_in_room(
+    async def get_insertion_event_backward_extremities_in_room(
         self, room_id
     ) -> Dict[str, int]:
         """Get the insertion events we know about that we haven't backfilled yet.
@@ -752,7 +752,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
             Map from event_id to depth
         """
 
-        def get_insertion_event_backwards_extremities_in_room_txn(txn, room_id):
+        def get_insertion_event_backward_extremities_in_room_txn(txn, room_id):
             sql = """
                 SELECT b.event_id, MAX(e.depth) FROM insertion_events as i
                 /* We only want insertion events that are also marked as backwards extremities */
@@ -768,8 +768,8 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
             return dict(txn)
 
         return await self.db_pool.runInteraction(
-            "get_insertion_event_backwards_extremities_in_room",
-            get_insertion_event_backwards_extremities_in_room_txn,
+            "get_insertion_event_backward_extremities_in_room",
+            get_insertion_event_backward_extremities_in_room_txn,
             room_id,
         )
 
@@ -1089,7 +1089,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         We also handle navigating historical branches of history connected by
         insertion and batch events.
         """
-        logger.info(
+        logger.debug(
             "_get_backfill_events(room_id=%s): seeding backfill with seed_event_id_list=%s limit=%s",
             room_id,
             seed_event_id_list,
@@ -1119,8 +1119,8 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
                 allow_none=True,
             )
 
-            logger.info(
-                "get_backfill_events(room_id=%s): seed_event_id=%s depth=%s stream_ordering=%s type=%s",
+            logger.debug(
+                "_get_backfill_events(room_id=%s): seed_event_id=%s depth=%s stream_ordering=%s type=%s",
                 room_id,
                 seed_event_id,
                 event_lookup_result["depth"],