Always notify replication when a stream advances (#14877)

This ensures that all other workers are told about stream updates in a timely manner, without having to remember to manually poke replication.

Author: erikjohnston

changelog.d/14877.misc

@@ -0,0 +1 @@
+Always notify replication when a stream advances automatically.

synapse/_scripts/synapse_port_db.py

@@ -51,6 +51,7 @@
     make_deferred_yieldable,
     run_in_background,
 )
+from synapse.notifier import ReplicationNotifier
 from synapse.storage.database import DatabasePool, LoggingTransaction, make_conn
 from synapse.storage.databases.main import PushRuleStore
 from synapse.storage.databases.main.account_data import AccountDataWorkerStore
@@ -260,6 +261,9 @@ def get_instance_name(self) -> str:
     def should_send_federation(self) -> bool:
         return False
 
+    def get_replication_notifier(self) -> ReplicationNotifier:
+        return ReplicationNotifier()
+
 
 class Porter:
     def __init__(

synapse/notifier.py

@@ -226,8 +226,7 @@ def __init__(self, hs: "HomeServer"):
         self.store = hs.get_datastores().main
         self.pending_new_room_events: List[_PendingRoomEventEntry] = []
 
-        # Called when there are new things to stream over replication
-        self.replication_callbacks: List[Callable[[], None]] = []
+        self._replication_notifier = hs.get_replication_notifier()
         self._new_join_in_room_callbacks: List[Callable[[str, str], None]] = []
 
         self._federation_client = hs.get_federation_http_client()
@@ -279,7 +278,7 @@ def add_replication_callback(self, cb: Callable[[], None]) -> None:
         it needs to do any asynchronous work, a background thread should be started and
         wrapped with run_as_background_process.
         """
-        self.replication_callbacks.append(cb)
+        self._replication_notifier.add_replication_callback(cb)
 
     def add_new_join_in_room_callback(self, cb: Callable[[str, str], None]) -> None:
         """Add a callback that will be called when a user joins a room.
@@ -741,8 +740,7 @@ def _user_joined_room(self, user_id: str, room_id: str) -> None:
 
     def notify_replication(self) -> None:
         """Notify the any replication listeners that there's a new event"""
-        for cb in self.replication_callbacks:
-            cb()
+        self._replication_notifier.notify_replication()
 
     def notify_user_joined_room(self, event_id: str, room_id: str) -> None:
         for cb in self._new_join_in_room_callbacks:
@@ -759,3 +757,26 @@ def notify_remote_server_up(self, server: str) -> None:
         # Tell the federation client about the fact the server is back up, so
         # that any in flight requests can be immediately retried.
         self._federation_client.wake_destination(server)
+
+
+@attr.s(auto_attribs=True)
+class ReplicationNotifier:
+    """Tracks callbacks for things that need to know about stream changes.
+
+    This is separate from the notifier to avoid circular dependencies.
+    """
+
+    _replication_callbacks: List[Callable[[], None]] = attr.Factory(list)
+
+    def add_replication_callback(self, cb: Callable[[], None]) -> None:
+        """Add a callback that will be called when some new data is available.
+        Callback is not given any arguments. It should *not* return a Deferred - if
+        it needs to do any asynchronous work, a background thread should be started and
+        wrapped with run_as_background_process.
+        """
+        self._replication_callbacks.append(cb)
+
+    def notify_replication(self) -> None:
+        """Notify the any replication listeners that there's a new event"""
+        for cb in self._replication_callbacks:
+            cb()

synapse/server.py

@@ -107,7 +107,7 @@
 from synapse.http.matrixfederationclient import MatrixFederationHttpClient
 from synapse.metrics.common_usage_metrics import CommonUsageMetricsManager
 from synapse.module_api import ModuleApi
-from synapse.notifier import Notifier
+from synapse.notifier import Notifier, ReplicationNotifier
 from synapse.push.bulk_push_rule_evaluator import BulkPushRuleEvaluator
 from synapse.push.pusherpool import PusherPool
 from synapse.replication.tcp.client import ReplicationDataHandler
@@ -389,6 +389,10 @@ def get_federation_server(self) -> FederationServer:
     def get_notifier(self) -> Notifier:
         return Notifier(self)
 
+    @cache_in_self
+    def get_replication_notifier(self) -> ReplicationNotifier:
+        return ReplicationNotifier()
+
     @cache_in_self
     def get_auth(self) -> Auth:
         return Auth(self)

synapse/storage/databases/main/account_data.py

@@ -75,6 +75,7 @@ def __init__(
             self._account_data_id_gen = MultiWriterIdGenerator(
                 db_conn=db_conn,
                 db=database,
+                notifier=hs.get_replication_notifier(),
                 stream_name="account_data",
                 instance_name=self._instance_name,
                 tables=[
@@ -95,6 +96,7 @@ def __init__(
             # SQLite).
             self._account_data_id_gen = StreamIdGenerator(
                 db_conn,
+                hs.get_replication_notifier(),
                 "room_account_data",
                 "stream_id",
                 extra_tables=[("room_tags_revisions", "stream_id")],

synapse/storage/databases/main/cache.py

@@ -75,6 +75,7 @@ def __init__(
             self._cache_id_gen = MultiWriterIdGenerator(
                 db_conn,
                 database,
+                notifier=hs.get_replication_notifier(),
                 stream_name="caches",
                 instance_name=hs.get_instance_name(),
                 tables=[

synapse/storage/databases/main/deviceinbox.py

@@ -91,6 +91,7 @@ def __init__(
                 MultiWriterIdGenerator(
                     db_conn=db_conn,
                     db=database,
+                    notifier=hs.get_replication_notifier(),
                     stream_name="to_device",
                     instance_name=self._instance_name,
                     tables=[("device_inbox", "instance_name", "stream_id")],
@@ -101,7 +102,7 @@ def __init__(
         else:
             self._can_write_to_device = True
             self._device_inbox_id_gen = StreamIdGenerator(
-                db_conn, "device_inbox", "stream_id"
+                db_conn, hs.get_replication_notifier(), "device_inbox", "stream_id"
             )
 
         max_device_inbox_id = self._device_inbox_id_gen.get_current_token()

synapse/storage/databases/main/devices.py

@@ -92,6 +92,7 @@ def __init__(
         # class below that is used on the main process.
         self._device_list_id_gen: AbstractStreamIdTracker = StreamIdGenerator(
             db_conn,
+            hs.get_replication_notifier(),
             "device_lists_stream",
             "stream_id",
             extra_tables=[

synapse/storage/databases/main/end_to_end_keys.py

@@ -1181,7 +1181,10 @@ def __init__(
         super().__init__(database, db_conn, hs)
 
         self._cross_signing_id_gen = StreamIdGenerator(
-            db_conn, "e2e_cross_signing_keys", "stream_id"
+            db_conn,
+            hs.get_replication_notifier(),
+            "e2e_cross_signing_keys",
+            "stream_id",
         )
 
     async def set_e2e_device_keys(

synapse/storage/databases/main/events_worker.py

@@ -191,6 +191,7 @@ def __init__(
             self._stream_id_gen = MultiWriterIdGenerator(
                 db_conn=db_conn,
                 db=database,
+                notifier=hs.get_replication_notifier(),
                 stream_name="events",
                 instance_name=hs.get_instance_name(),
                 tables=[("events", "instance_name", "stream_ordering")],
@@ -200,6 +201,7 @@ def __init__(
             self._backfill_id_gen = MultiWriterIdGenerator(
                 db_conn=db_conn,
                 db=database,
+                notifier=hs.get_replication_notifier(),
                 stream_name="backfill",
                 instance_name=hs.get_instance_name(),
                 tables=[("events", "instance_name", "stream_ordering")],
@@ -217,12 +219,14 @@ def __init__(
             # SQLite).
             self._stream_id_gen = StreamIdGenerator(
                 db_conn,
+                hs.get_replication_notifier(),
                 "events",
                 "stream_ordering",
                 is_writer=hs.get_instance_name() in hs.config.worker.writers.events,
             )
             self._backfill_id_gen = StreamIdGenerator(
                 db_conn,
+                hs.get_replication_notifier(),
                 "events",
                 "stream_ordering",
                 step=-1,
@@ -300,6 +304,7 @@ def get_chain_id_txn(txn: Cursor) -> int:
             self._un_partial_stated_events_stream_id_gen = MultiWriterIdGenerator(
                 db_conn=db_conn,
                 db=database,
+                notifier=hs.get_replication_notifier(),
                 stream_name="un_partial_stated_event_stream",
                 instance_name=hs.get_instance_name(),
                 tables=[
@@ -311,7 +316,10 @@ def get_chain_id_txn(txn: Cursor) -> int:
             )
         else:
             self._un_partial_stated_events_stream_id_gen = StreamIdGenerator(
-                db_conn, "un_partial_stated_event_stream", "stream_id"
+                db_conn,
+                hs.get_replication_notifier(),
+                "un_partial_stated_event_stream",
+                "stream_id",
             )
 
     def get_un_partial_stated_events_token(self) -> int:

synapse/storage/databases/main/presence.py

@@ -77,6 +77,7 @@ def __init__(
             self._presence_id_gen = MultiWriterIdGenerator(
                 db_conn=db_conn,
                 db=database,
+                notifier=hs.get_replication_notifier(),
                 stream_name="presence_stream",
                 instance_name=self._instance_name,
                 tables=[("presence_stream", "instance_name", "stream_id")],
@@ -85,7 +86,7 @@ def __init__(
             )
         else:
             self._presence_id_gen = StreamIdGenerator(
-                db_conn, "presence_stream", "stream_id"
+                db_conn, hs.get_replication_notifier(), "presence_stream", "stream_id"
             )
 
         self.hs = hs

synapse/storage/databases/main/push_rule.py

@@ -118,6 +118,7 @@ def __init__(
         # class below that is used on the main process.
         self._push_rules_stream_id_gen: AbstractStreamIdTracker = StreamIdGenerator(
             db_conn,
+            hs.get_replication_notifier(),
             "push_rules_stream",
             "stream_id",
             is_writer=hs.config.worker.worker_app is None,

synapse/storage/databases/main/pusher.py

@@ -62,6 +62,7 @@ def __init__(
         # class below that is used on the main process.
         self._pushers_id_gen: AbstractStreamIdTracker = StreamIdGenerator(
             db_conn,
+            hs.get_replication_notifier(),
             "pushers",
             "id",
             extra_tables=[("deleted_pushers", "stream_id")],

synapse/storage/databases/main/receipts.py

@@ -73,6 +73,7 @@ def __init__(
             self._receipts_id_gen = MultiWriterIdGenerator(
                 db_conn=db_conn,
                 db=database,
+                notifier=hs.get_replication_notifier(),
                 stream_name="receipts",
                 instance_name=self._instance_name,
                 tables=[("receipts_linearized", "instance_name", "stream_id")],
@@ -91,6 +92,7 @@ def __init__(
             # SQLite).
             self._receipts_id_gen = StreamIdGenerator(
                 db_conn,
+                hs.get_replication_notifier(),
                 "receipts_linearized",
                 "stream_id",
                 is_writer=hs.get_instance_name() in hs.config.worker.writers.receipts,

synapse/storage/databases/main/room.py

@@ -126,6 +126,7 @@ def __init__(
             self._un_partial_stated_rooms_stream_id_gen = MultiWriterIdGenerator(
                 db_conn=db_conn,
                 db=database,
+                notifier=hs.get_replication_notifier(),
                 stream_name="un_partial_stated_room_stream",
                 instance_name=self._instance_name,
                 tables=[
@@ -137,7 +138,10 @@ def __init__(
             )
         else:
             self._un_partial_stated_rooms_stream_id_gen = StreamIdGenerator(
-                db_conn, "un_partial_stated_room_stream", "stream_id"
+                db_conn,
+                hs.get_replication_notifier(),
+                "un_partial_stated_room_stream",
+                "stream_id",
             )
 
     async def store_room(

synapse/storage/util/id_generators.py

@@ -20,6 +20,7 @@
 from contextlib import contextmanager
 from types import TracebackType
 from typing import (
+    TYPE_CHECKING,
     AsyncContextManager,
     ContextManager,
     Dict,
@@ -49,6 +50,9 @@
 from synapse.storage.types import Cursor
 from synapse.storage.util.sequence import PostgresSequenceGenerator
 
+if TYPE_CHECKING:
+    from synapse.notifier import ReplicationNotifier
+
 logger = logging.getLogger(__name__)
 
 
@@ -182,6 +186,7 @@ class StreamIdGenerator(AbstractStreamIdGenerator):
     def __init__(
         self,
         db_conn: LoggingDatabaseConnection,
+        notifier: "ReplicationNotifier",
         table: str,
         column: str,
         extra_tables: Iterable[Tuple[str, str]] = (),
@@ -205,6 +210,8 @@ def __init__(
         # The key and values are the same, but we never look at the values.
         self._unfinished_ids: OrderedDict[int, int] = OrderedDict()
 
+        self._notifier = notifier
+
     def advance(self, instance_name: str, new_id: int) -> None:
         # Advance should never be called on a writer instance, only over replication
         if self._is_writer:
@@ -227,6 +234,8 @@ def manager() -> Generator[int, None, None]:
                 with self._lock:
                     self._unfinished_ids.pop(next_id)
 
+                self._notifier.notify_replication()
+
         return _AsyncCtxManagerWrapper(manager())
 
     def get_next_mult(self, n: int) -> AsyncContextManager[Sequence[int]]:
@@ -250,6 +259,8 @@ def manager() -> Generator[Sequence[int], None, None]:
                     for next_id in next_ids:
                         self._unfinished_ids.pop(next_id)
 
+                self._notifier.notify_replication()
+
         return _AsyncCtxManagerWrapper(manager())
 
     def get_current_token(self) -> int:
@@ -296,6 +307,7 @@ def __init__(
         self,
         db_conn: LoggingDatabaseConnection,
         db: DatabasePool,
+        notifier: "ReplicationNotifier",
         stream_name: str,
         instance_name: str,
         tables: List[Tuple[str, str, str]],
@@ -304,6 +316,7 @@ def __init__(
         positive: bool = True,
     ) -> None:
         self._db = db
+        self._notifier = notifier
         self._stream_name = stream_name
         self._instance_name = instance_name
         self._positive = positive
@@ -535,7 +548,9 @@ def get_next(self) -> AsyncContextManager[int]:
         # Cast safety: the second argument to _MultiWriterCtxManager, multiple_ids,
         # controls the return type. If `None` or omitted, the context manager yields
         # a single integer stream_id; otherwise it yields a list of stream_ids.
-        return cast(AsyncContextManager[int], _MultiWriterCtxManager(self))
+        return cast(
+            AsyncContextManager[int], _MultiWriterCtxManager(self, self._notifier)
+        )
 
     def get_next_mult(self, n: int) -> AsyncContextManager[List[int]]:
         # If we have a list of instances that are allowed to write to this
@@ -544,7 +559,10 @@ def get_next_mult(self, n: int) -> AsyncContextManager[List[int]]:
             raise Exception("Tried to allocate stream ID on non-writer")
 
         # Cast safety: see get_next.
-        return cast(AsyncContextManager[List[int]], _MultiWriterCtxManager(self, n))
+        return cast(
+            AsyncContextManager[List[int]],
+            _MultiWriterCtxManager(self, self._notifier, n),
+        )
 
     def get_next_txn(self, txn: LoggingTransaction) -> int:
         """
@@ -563,6 +581,7 @@ def get_next_txn(self, txn: LoggingTransaction) -> int:
 
         txn.call_after(self._mark_id_as_finished, next_id)
         txn.call_on_exception(self._mark_id_as_finished, next_id)
+        txn.call_after(self._notifier.notify_replication)
 
         # Update the `stream_positions` table with newly updated stream
         # ID (unless self._writers is not set in which case we don't
@@ -787,6 +806,7 @@ class _MultiWriterCtxManager:
     """Async context manager returned by MultiWriterIdGenerator"""
 
     id_gen: MultiWriterIdGenerator
+    notifier: "ReplicationNotifier"
     multiple_ids: Optional[int] = None
     stream_ids: List[int] = attr.Factory(list)
 
@@ -814,6 +834,8 @@ async def __aexit__(
         for i in self.stream_ids:
             self.id_gen._mark_id_as_finished(i)
 
+        self.notifier.notify_replication()
+
         if exc_type is not None:
             return False