Prep work for removing outlier from internal_metadata

changelog.d/9411.misc

@@ -0,0 +1 @@
+Preparatory steps for removing redundant `outlier` data from `event_json.internal_metadata` column.

synapse/events/__init__.py

@@ -98,7 +98,7 @@ def __get__(self, instance, owner=None):
 
 
 class _EventInternalMetadata:
-    __slots__ = ["_dict", "stream_ordering"]
+    __slots__ = ["_dict", "stream_ordering", "outlier"]
 
     def __init__(self, internal_metadata_dict: JsonDict):
         # we have to copy the dict, because it turns out that the same dict is
@@ -108,7 +108,10 @@ def __init__(self, internal_metadata_dict: JsonDict):
         # the stream ordering of this event. None, until it has been persisted.
         self.stream_ordering = None  # type: Optional[int]
 
-    outlier = DictProperty("outlier")  # type: bool
+        # whether this event is an outlier (ie, whether we have the state at that point
+        # in the DAG)
+        self.outlier = False
+
     out_of_band_membership = DictProperty("out_of_band_membership")  # type: bool
     send_on_behalf_of = DictProperty("send_on_behalf_of")  # type: str
     recheck_redaction = DictProperty("recheck_redaction")  # type: bool
@@ -129,7 +132,7 @@ def get_dict(self) -> JsonDict:
         return dict(self._dict)
 
     def is_outlier(self) -> bool:
-        return self._dict.get("outlier", False)
+        return self.outlier
 
     def is_out_of_band_membership(self) -> bool:
         """Whether this is an out of band membership, like an invite or an invite

synapse/events/utils.py

@@ -54,6 +54,8 @@ def prune_event(event: EventBase) -> EventBase:
         event.internal_metadata.stream_ordering
     )
 
+    pruned_event.internal_metadata.outlier = event.internal_metadata.outlier
+
     # Mark the event as redacted
     pruned_event.internal_metadata.redacted = True
 

synapse/replication/http/federation.py

@@ -40,6 +40,7 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
                                     // containing the event
                 "event_format_version": .., // 1,2,3 etc: the event format version
                 "internal_metadata": { .. serialized internal_metadata .. },
+                "outlier": true|false,
                 "rejected_reason": ..,   // The event.rejected_reason field
                 "context": { .. serialized event context .. },
             }],
@@ -84,6 +85,7 @@ async def _serialize_payload(store, room_id, event_and_contexts, backfilled):
                     "room_version": event.room_version.identifier,
                     "event_format_version": event.format_version,
                     "internal_metadata": event.internal_metadata.get_dict(),
+                    "outlier": event.internal_metadata.is_outlier(),
                     "rejected_reason": event.rejected_reason,
                     "context": serialized_context,
                 }
@@ -116,6 +118,7 @@ async def _handle_request(self, request):
                 event = make_event_from_dict(
                     event_dict, room_ver, internal_metadata, rejected_reason
                 )
+                event.internal_metadata.outlier = event_payload["outlier"]
 
                 context = EventContext.deserialize(
                     self.storage, event_payload["context"]

synapse/replication/http/send_event.py

@@ -80,6 +80,10 @@ async def _serialize_payload(
             extra_users (list(UserID)): Any extra users to notify about event
         """
 
+        # we only expect this interface to be used for local events, so they shouldn't
+        # be outliers.
+        assert not event.internal_metadata.is_outlier()
+
         serialized_context = await context.serialize(event, store)
 
         payload = {

synapse/storage/databases/main/events.py

@@ -1270,8 +1270,10 @@ def _update_outliers_txn(self, txn, events_and_contexts):
                     logger.exception("")
                     raise
 
+                # update the stored internal_metadata to update the "outlier" flag.
+                # TODO: This is unused as of Synapse 1.30. Remove it once we are happy
+                #  to drop backwards-compatibility with 1.29.
                 metadata_json = json_encoder.encode(event.internal_metadata.get_dict())
-
                 sql = "UPDATE event_json SET internal_metadata = ? WHERE event_id = ?"
                 txn.execute(sql, (metadata_json, event.event_id))
 
@@ -1319,6 +1321,19 @@ def event_dict(event):
             d.pop("redacted_because", None)
             return d
 
+        def get_internal_metadata(event):
+            im = event.internal_metadata.get_dict()
+
+            # temporary hack for database compatibility with Synapse 1.29 and earlier:
+            # store the `outlier` flag inside the internal_metadata json as well as in
+            # the `events` table, so that if anyone rolls back to an older Synapse,
+            # things keep working. This can be removed once we are happy to drop support
+            # for that
+            if event.internal_metadata.is_outlier():
+                im["outlier"] = True
+
+            return im
+
         self.db_pool.simple_insert_many_txn(
             txn,
             table="event_json",
@@ -1327,7 +1342,7 @@ def event_dict(event):
                     "event_id": event.event_id,
                     "room_id": event.room_id,
                     "internal_metadata": json_encoder.encode(
-                        event.internal_metadata.get_dict()
+                        get_internal_metadata(event)
                     ),
                     "json": json_encoder.encode(event_dict(event)),
                     "format_version": event.format_version,

synapse/storage/databases/main/events_worker.py

@@ -799,6 +799,7 @@ async def _get_events_from_db(self, event_ids, allow_rejected=False):
                 rejected_reason=rejected_reason,
             )
             original_ev.internal_metadata.stream_ordering = row["stream_ordering"]
+            original_ev.internal_metadata.outlier = row["outlier"]
 
             event_map[event_id] = original_ev
 
@@ -905,7 +906,8 @@ def _fetch_event_rows(self, txn, event_ids):
                   ej.json,
                   ej.format_version,
                   r.room_version,
-                  rej.reason
+                  rej.reason,
+                  e.outlier
                 FROM events AS e
                   JOIN event_json AS ej USING (event_id)
                   LEFT JOIN rooms r ON r.room_id = e.room_id
@@ -929,6 +931,7 @@ def _fetch_event_rows(self, txn, event_ids):
                     "room_version_id": row[5],
                     "rejected_reason": row[6],
                     "redactions": [],
+                    "outlier": row[7],
                 }
 
             # check for redactions