diff options
Diffstat (limited to 'synapse/federation/sender')
| -rw-r--r-- | synapse/federation/sender/per_destination_queue.py | 104 |
1 files changed, 89 insertions, 15 deletions
diff --git a/synapse/federation/sender/per_destination_queue.py b/synapse/federation/sender/per_destination_queue.py index cc0d765e5f..af85fe0a1e 100644 --- a/synapse/federation/sender/per_destination_queue.py +++ b/synapse/federation/sender/per_destination_queue.py @@ -15,7 +15,7 @@ # limitations under the License. import datetime import logging -from typing import TYPE_CHECKING, Dict, Hashable, Iterable, List, Optional, Tuple, cast +from typing import TYPE_CHECKING, Dict, Hashable, Iterable, List, Optional, Tuple import attr from prometheus_client import Counter @@ -77,6 +77,7 @@ class PerDestinationQueue: self._transaction_manager = transaction_manager self._instance_name = hs.get_instance_name() self._federation_shard_config = hs.config.worker.federation_shard_config + self._state = hs.get_state_handler() self._should_send_on_this_instance = True if not self._federation_shard_config.should_handle( @@ -415,22 +416,95 @@ class PerDestinationQueue: "This should not happen." % event_ids ) - if logger.isEnabledFor(logging.INFO): - rooms = [p.room_id for p in catchup_pdus] - logger.info("Catching up rooms to %s: %r", self._destination, rooms) + # We send transactions with events from one room only, as its likely + # that the remote will have to do additional processing, which may + # take some time. It's better to give it small amounts of work + # rather than risk the request timing out and repeatedly being + # retried, and not making any progress. + # + # Note: `catchup_pdus` will have exactly one PDU per room. + for pdu in catchup_pdus: + # The PDU from the DB will be the last PDU in the room from + # *this server* that wasn't sent to the remote. However, other + # servers may have sent lots of events since then, and we want + # to try and tell the remote only about the *latest* events in + # the room. This is so that it doesn't get inundated by events + # from various parts of the DAG, which all need to be processed. + # + # Note: this does mean that in large rooms a server coming back + # online will get sent the same events from all the different + # servers, but the remote will correctly deduplicate them and + # handle it only once. + + # Step 1, fetch the current extremities + extrems = await self._store.get_prev_events_for_room(pdu.room_id) + + if pdu.event_id in extrems: + # If the event is in the extremities, then great! We can just + # use that without having to do further checks. + room_catchup_pdus = [pdu] + else: + # If not, fetch the extremities and figure out which we can + # send. + extrem_events = await self._store.get_events_as_list(extrems) + + new_pdus = [] + for p in extrem_events: + # We pulled this from the DB, so it'll be non-null + assert p.internal_metadata.stream_ordering + + # Filter out events that happened before the remote went + # offline + if ( + p.internal_metadata.stream_ordering + < self._last_successful_stream_ordering + ): + continue - await self._transaction_manager.send_new_transaction( - self._destination, catchup_pdus, [] - ) + # Filter out events where the server is not in the room, + # e.g. it may have left/been kicked. *Ideally* we'd pull + # out the kick and send that, but it's a rare edge case + # so we don't bother for now (the server that sent the + # kick should send it out if its online). + hosts = await self._state.get_hosts_in_room_at_events( + p.room_id, [p.event_id] + ) + if self._destination not in hosts: + continue - sent_transactions_counter.inc() - final_pdu = catchup_pdus[-1] - self._last_successful_stream_ordering = cast( - int, final_pdu.internal_metadata.stream_ordering - ) - await self._store.set_destination_last_successful_stream_ordering( - self._destination, self._last_successful_stream_ordering - ) + new_pdus.append(p) + + # If we've filtered out all the extremities, fall back to + # sending the original event. This should ensure that the + # server gets at least some of missed events (especially if + # the other sending servers are up). + if new_pdus: + room_catchup_pdus = new_pdus + + logger.info( + "Catching up rooms to %s: %r", self._destination, pdu.room_id + ) + + await self._transaction_manager.send_new_transaction( + self._destination, room_catchup_pdus, [] + ) + + sent_transactions_counter.inc() + + # We pulled this from the DB, so it'll be non-null + assert pdu.internal_metadata.stream_ordering + + # Note that we mark the last successful stream ordering as that + # from the *original* PDU, rather than the PDU(s) we actually + # send. This is because we use it to mark our position in the + # queue of missed PDUs to process. + self._last_successful_stream_ordering = ( + pdu.internal_metadata.stream_ordering + ) + + await self._store.set_destination_last_successful_stream_ordering( + self._destination, self._last_successful_stream_ordering + ) def _get_rr_edus(self, force_flush: bool) -> Iterable[Edu]: if not self._pending_rrs: |