diff --git a/changelog.d/8230.misc b/changelog.d/8230.misc
new file mode 100644
index 0000000000..bf0ba76730
--- /dev/null
+++ b/changelog.d/8230.misc
@@ -0,0 +1 @@
+Track the latest event for every destination and room for catch-up after federation outage.
diff --git a/synapse/federation/sender/__init__.py b/synapse/federation/sender/__init__.py
index 552519e82c..41a726878d 100644
--- a/synapse/federation/sender/__init__.py
+++ b/synapse/federation/sender/__init__.py
@@ -209,7 +209,7 @@ class FederationSender:
logger.debug("Sending %s to %r", event, destinations)
if destinations:
- self._send_pdu(event, destinations)
+ await self._send_pdu(event, destinations)
now = self.clock.time_msec()
ts = await self.store.get_received_ts(event.event_id)
@@ -265,7 +265,7 @@ class FederationSender:
finally:
self._is_processing = False
- def _send_pdu(self, pdu: EventBase, destinations: Iterable[str]) -> None:
+ async def _send_pdu(self, pdu: EventBase, destinations: Iterable[str]) -> None:
# We loop through all destinations to see whether we already have
# a transaction in progress. If we do, stick it in the pending_pdus
# table and we'll get back to it later.
@@ -280,6 +280,13 @@ class FederationSender:
sent_pdus_destination_dist_total.inc(len(destinations))
sent_pdus_destination_dist_count.inc()
+ # track the fact that we have a PDU for these destinations,
+ # to allow us to perform catch-up later on if the remote is unreachable
+ # for a while.
+ await self.store.store_destination_rooms_entries(
+ destinations, pdu.room_id, pdu.internal_metadata.stream_ordering,
+ )
+
for destination in destinations:
self._get_per_destination_queue(destination).send_pdu(pdu)
diff --git a/synapse/storage/database.py b/synapse/storage/database.py
index ed8a9bffb1..79ec8f119d 100644
--- a/synapse/storage/database.py
+++ b/synapse/storage/database.py
@@ -952,7 +952,7 @@ class DatabasePool:
key_names: Collection[str],
key_values: Collection[Iterable[Any]],
value_names: Collection[str],
- value_values: Iterable[Iterable[str]],
+ value_values: Iterable[Iterable[Any]],
) -> None:
"""
Upsert, many times.
@@ -981,7 +981,7 @@ class DatabasePool:
key_names: Iterable[str],
key_values: Collection[Iterable[Any]],
value_names: Collection[str],
- value_values: Iterable[Iterable[str]],
+ value_values: Iterable[Iterable[Any]],
) -> None:
"""
Upsert, many times, but without native UPSERT support or batching.
diff --git a/synapse/storage/databases/main/purge_events.py b/synapse/storage/databases/main/purge_events.py
index ea833829ae..d7a03cbf7d 100644
--- a/synapse/storage/databases/main/purge_events.py
+++ b/synapse/storage/databases/main/purge_events.py
@@ -69,6 +69,7 @@ class PurgeEventsStore(StateGroupWorkerStore, SQLBaseStore):
# room_depth
# state_groups
# state_groups_state
+ # destination_rooms
# we will build a temporary table listing the events so that we don't
# have to keep shovelling the list back and forth across the
@@ -336,6 +337,7 @@ class PurgeEventsStore(StateGroupWorkerStore, SQLBaseStore):
# and finally, the tables with an index on room_id (or no useful index)
for table in (
"current_state_events",
+ "destination_rooms",
"event_backward_extremities",
"event_forward_extremities",
"event_json",
diff --git a/synapse/storage/databases/main/schema/delta/58/15_catchup_destination_rooms.sql b/synapse/storage/databases/main/schema/delta/58/15_catchup_destination_rooms.sql
new file mode 100644
index 0000000000..7f173f10d4
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/15_catchup_destination_rooms.sql
@@ -0,0 +1,42 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+-- This schema delta alters the schema to enable 'catching up' remote homeservers
+-- after there has been a connectivity problem for any reason.
+
+-- This stores, for each (destination, room) pair, the stream_ordering of the
+-- latest event for that destination.
+CREATE TABLE IF NOT EXISTS destination_rooms (
+ -- the destination in question.
+ destination TEXT NOT NULL REFERENCES destinations (destination),
+ -- the ID of the room in question
+ room_id TEXT NOT NULL REFERENCES rooms (room_id),
+ -- the stream_ordering of the event
+ stream_ordering INTEGER NOT NULL,
+ PRIMARY KEY (destination, room_id)
+ -- We don't declare a foreign key on stream_ordering here because that'd mean
+ -- we'd need to either maintain an index (expensive) or do a table scan of
+ -- destination_rooms whenever we delete an event (also potentially expensive).
+ -- In addition to that, a foreign key on stream_ordering would be redundant
+ -- as this row doesn't need to refer to a specific event; if the event gets
+ -- deleted then it doesn't affect the validity of the stream_ordering here.
+);
+
+-- This index is needed to make it so that a deletion of a room (in the rooms
+-- table) can be efficient, as otherwise a table scan would need to be performed
+-- to check that no destination_rooms rows point to the room to be deleted.
+-- Also: it makes it efficient to delete all the entries for a given room ID,
+-- such as when purging a room.
+CREATE INDEX IF NOT EXISTS destination_rooms_room_id
+ ON destination_rooms (room_id);
diff --git a/synapse/storage/databases/main/transactions.py b/synapse/storage/databases/main/transactions.py
index 5b31aab700..efc425f95d 100644
--- a/synapse/storage/databases/main/transactions.py
+++ b/synapse/storage/databases/main/transactions.py
@@ -15,13 +15,14 @@
import logging
from collections import namedtuple
-from typing import Optional, Tuple
+from typing import Iterable, Optional, Tuple
from canonicaljson import encode_canonical_json
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.storage._base import SQLBaseStore, db_to_json
-from synapse.storage.database import DatabasePool
+from synapse.storage.database import DatabasePool, LoggingTransaction
+from synapse.storage.engines import PostgresEngine, Sqlite3Engine
from synapse.types import JsonDict
from synapse.util.caches.expiringcache import ExpiringCache
@@ -164,7 +165,9 @@ class TransactionStore(SQLBaseStore):
allow_none=True,
)
- if result and result["retry_last_ts"] > 0:
+ # check we have a row and retry_last_ts is not null or zero
+ # (retry_last_ts can't be negative)
+ if result and result["retry_last_ts"]:
return result
else:
return None
@@ -273,3 +276,60 @@ class TransactionStore(SQLBaseStore):
await self.db_pool.runInteraction(
"_cleanup_transactions", _cleanup_transactions_txn
)
+
+ async def store_destination_rooms_entries(
+ self, destinations: Iterable[str], room_id: str, stream_ordering: int,
+ ) -> None:
+ """
+ Updates or creates `destination_rooms` entries in batch for a single event.
+
+ Args:
+ destinations: list of destinations
+ room_id: the room_id of the event
+ stream_ordering: the stream_ordering of the event
+ """
+
+ return await self.db_pool.runInteraction(
+ "store_destination_rooms_entries",
+ self._store_destination_rooms_entries_txn,
+ destinations,
+ room_id,
+ stream_ordering,
+ )
+
+ def _store_destination_rooms_entries_txn(
+ self,
+ txn: LoggingTransaction,
+ destinations: Iterable[str],
+ room_id: str,
+ stream_ordering: int,
+ ) -> None:
+
+ # ensure we have a `destinations` row for this destination, as there is
+ # a foreign key constraint.
+ if isinstance(self.database_engine, PostgresEngine):
+ q = """
+ INSERT INTO destinations (destination)
+ VALUES (?)
+ ON CONFLICT DO NOTHING;
+ """
+ elif isinstance(self.database_engine, Sqlite3Engine):
+ q = """
+ INSERT OR IGNORE INTO destinations (destination)
+ VALUES (?);
+ """
+ else:
+ raise RuntimeError("Unknown database engine")
+
+ txn.execute_batch(q, ((destination,) for destination in destinations))
+
+ rows = [(destination, room_id) for destination in destinations]
+
+ self.db_pool.simple_upsert_many_txn(
+ txn,
+ "destination_rooms",
+ ["destination", "room_id"],
+ rows,
+ ["stream_ordering"],
+ [(stream_ordering,)] * len(rows),
+ )
diff --git a/tests/federation/test_federation_catch_up.py b/tests/federation/test_federation_catch_up.py
new file mode 100644
index 0000000000..73c51c9d6c
--- /dev/null
+++ b/tests/federation/test_federation_catch_up.py
@@ -0,0 +1,82 @@
+from mock import Mock
+
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
+
+from tests.test_utils import event_injection, make_awaitable
+from tests.unittest import FederatingHomeserverTestCase, override_config
+
+
+class FederationCatchUpTestCases(FederatingHomeserverTestCase):
+ servlets = [
+ admin.register_servlets,
+ room.register_servlets,
+ login.register_servlets,
+ ]
+
+ def make_homeserver(self, reactor, clock):
+ return self.setup_test_homeserver(
+ federation_transport_client=Mock(spec=["send_transaction"]),
+ )
+
+ def prepare(self, reactor, clock, hs):
+ # stub out get_current_hosts_in_room
+ state_handler = hs.get_state_handler()
+
+ # This mock is crucial for destination_rooms to be populated.
+ state_handler.get_current_hosts_in_room = Mock(
+ return_value=make_awaitable(["test", "host2"])
+ )
+
+ def get_destination_room(self, room: str, destination: str = "host2") -> dict:
+ """
+ Gets the destination_rooms entry for a (destination, room_id) pair.
+
+ Args:
+ room: room ID
+ destination: what destination, default is "host2"
+
+ Returns:
+ Dictionary of { event_id: str, stream_ordering: int }
+ """
+ event_id, stream_ordering = self.get_success(
+ self.hs.get_datastore().db_pool.execute(
+ "test:get_destination_rooms",
+ None,
+ """
+ SELECT event_id, stream_ordering
+ FROM destination_rooms dr
+ JOIN events USING (stream_ordering)
+ WHERE dr.destination = ? AND dr.room_id = ?
+ """,
+ destination,
+ room,
+ )
+ )[0]
+ return {"event_id": event_id, "stream_ordering": stream_ordering}
+
+ @override_config({"send_federation": True})
+ def test_catch_up_destination_rooms_tracking(self):
+ """
+ Tests that we populate the `destination_rooms` table as needed.
+ """
+ self.register_user("u1", "you the one")
+ u1_token = self.login("u1", "you the one")
+ room = self.helper.create_room_as("u1", tok=u1_token)
+
+ self.get_success(
+ event_injection.inject_member_event(self.hs, room, "@user:host2", "join")
+ )
+
+ event_id_1 = self.helper.send(room, "wombats!", tok=u1_token)["event_id"]
+
+ row_1 = self.get_destination_room(room)
+
+ event_id_2 = self.helper.send(room, "rabbits!", tok=u1_token)["event_id"]
+
+ row_2 = self.get_destination_room(room)
+
+ # check: events correctly registered in order
+ self.assertEqual(row_1["event_id"], event_id_1)
+ self.assertEqual(row_2["event_id"], event_id_2)
+ self.assertEqual(row_1["stream_ordering"], row_2["stream_ordering"] - 1)
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