Rework groups in the stream token.

synapse/storage/databases/main/__init__.py

@@ -152,9 +152,6 @@ def __init__(
 
         self._push_rule_id_gen = IdGenerator(db_conn, "push_rules", "id")
         self._push_rules_enable_id_gen = IdGenerator(db_conn, "push_rules_enable", "id")
-        self._group_updates_id_gen = StreamIdGenerator(
-            db_conn, "local_group_updates", "stream_id"
-        )
 
         self._cache_id_gen: Optional[MultiWriterIdGenerator]
         if isinstance(self.database_engine, PostgresEngine):
@@ -198,20 +195,6 @@ def __init__(
             prefilled_cache=curr_state_delta_prefill,
         )
 
-        _group_updates_prefill, min_group_updates_id = self.db_pool.get_cache_dict(
-            db_conn,
-            "local_group_updates",
-            entity_column="user_id",
-            stream_column="stream_id",
-            max_value=self._group_updates_id_gen.get_current_token(),
-            limit=1000,
-        )
-        self._group_updates_stream_cache = StreamChangeCache(
-            "_group_updates_stream_cache",
-            min_group_updates_id,
-            prefilled_cache=_group_updates_prefill,
-        )
-
         self._stream_order_on_start = self.get_room_max_stream_ordering()
         self._min_stream_order_on_start = self.get_room_min_stream_ordering()
 

synapse/storage/databases/main/group_server.py

@@ -32,6 +32,3 @@ def __init__(
         # Register a legacy groups background update as a no-op.
         database.updates.register_noop_background_update("local_group_updates_index")
         super().__init__(database, db_conn, hs)
-
-    def get_group_stream_token(self) -> int:
-        return self._group_updates_id_gen.get_current_token()  # type: ignore[attr-defined]

synapse/streams/events.py

@@ -54,7 +54,6 @@ def get_current_token(self) -> StreamToken:
         push_rules_key = self.store.get_max_push_rules_stream_id()
         to_device_key = self.store.get_to_device_stream_token()
         device_list_key = self.store.get_device_stream_token()
-        groups_key = self.store.get_group_stream_token()
 
         token = StreamToken(
             room_key=self.sources.room.get_current_key(),
@@ -65,7 +64,8 @@ def get_current_token(self) -> StreamToken:
             push_rules_key=push_rules_key,
             to_device_key=to_device_key,
             device_list_key=device_list_key,
-            groups_key=groups_key,
+            # Groups key is unused.
+            groups_key=0,
         )
         return token
 

synapse/types.py

@@ -670,6 +670,7 @@ class StreamToken:
     push_rules_key: int
     to_device_key: int
     device_list_key: int
+    # Note that the groups key is no longer used and may have bogus values.
     groups_key: int
 
     _SEPARATOR = "_"
@@ -701,6 +702,9 @@ async def to_string(self, store: "DataStore") -> str:
                 str(self.push_rules_key),
                 str(self.to_device_key),
                 str(self.device_list_key),
+                # Note that the groups key is no longer used, but it is still
+                # serialized so that there will not be confusion in the future
+                # if additional tokens are added.
                 str(self.groups_key),
             ]
         )