diff options
Diffstat (limited to 'synapse/handlers/federation.py')
| -rw-r--r-- | synapse/handlers/federation.py | 109 |
1 files changed, 61 insertions, 48 deletions
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index 360ab6fee2..500c1c16d0 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -38,7 +38,7 @@ from signedjson.sign import verify_signed_json from unpaddedbase64 import decode_base64 from synapse import event_auth -from synapse.api.constants import EventContentFields, EventTypes, Membership +from synapse.api.constants import MAX_DEPTH, EventContentFields, EventTypes, Membership from synapse.api.errors import ( AuthError, CodeMessageException, @@ -211,7 +211,7 @@ class FederationHandler: current_depth: int, limit: int, *, - processing_start_time: int, + processing_start_time: Optional[int], ) -> bool: """ Checks whether the `current_depth` is at or approaching any backfill @@ -223,12 +223,23 @@ class FederationHandler: room_id: The room to backfill in. current_depth: The depth to check at for any upcoming backfill points. limit: The max number of events to request from the remote federated server. - processing_start_time: The time when `maybe_backfill` started - processing. Only used for timing. + processing_start_time: The time when `maybe_backfill` started processing. + Only used for timing. If `None`, no timing observation will be made. """ backwards_extremities = [ _BackfillPoint(event_id, depth, _BackfillPointType.BACKWARDS_EXTREMITY) - for event_id, depth in await self.store.get_backfill_points_in_room(room_id) + for event_id, depth in await self.store.get_backfill_points_in_room( + room_id=room_id, + current_depth=current_depth, + # We only need to end up with 5 extremities combined with the + # insertion event extremities to make the `/backfill` request + # but fetch an order of magnitude more to make sure there is + # enough even after we filter them by whether visible in the + # history. This isn't fool-proof as all backfill points within + # our limit could be filtered out but seems like a good amount + # to try with at least. + limit=50, + ) ] insertion_events_to_be_backfilled: List[_BackfillPoint] = [] @@ -236,7 +247,12 @@ class FederationHandler: insertion_events_to_be_backfilled = [ _BackfillPoint(event_id, depth, _BackfillPointType.INSERTION_PONT) for event_id, depth in await self.store.get_insertion_event_backward_extremities_in_room( - room_id + room_id=room_id, + current_depth=current_depth, + # We only need to end up with 5 extremities combined with + # the backfill points to make the `/backfill` request ... + # (see the other comment above for more context). + limit=50, ) ] logger.debug( @@ -245,10 +261,6 @@ class FederationHandler: insertion_events_to_be_backfilled, ) - if not backwards_extremities and not insertion_events_to_be_backfilled: - logger.debug("Not backfilling as no extremeties found.") - return False - # we now have a list of potential places to backpaginate from. We prefer to # start with the most recent (ie, max depth), so let's sort the list. sorted_backfill_points: List[_BackfillPoint] = sorted( @@ -269,6 +281,33 @@ class FederationHandler: sorted_backfill_points, ) + # If we have no backfill points lower than the `current_depth` then + # either we can a) bail or b) still attempt to backfill. We opt to try + # backfilling anyway just in case we do get relevant events. + if not sorted_backfill_points and current_depth != MAX_DEPTH: + logger.debug( + "_maybe_backfill_inner: all backfill points are *after* current depth. Trying again with later backfill points." + ) + return await self._maybe_backfill_inner( + room_id=room_id, + # We use `MAX_DEPTH` so that we find all backfill points next + # time (all events are below the `MAX_DEPTH`) + current_depth=MAX_DEPTH, + limit=limit, + # We don't want to start another timing observation from this + # nested recursive call. The top-most call can record the time + # overall otherwise the smaller one will throw off the results. + processing_start_time=None, + ) + + # Even after recursing with `MAX_DEPTH`, we didn't find any + # backward extremities to backfill from. + if not sorted_backfill_points: + logger.debug( + "_maybe_backfill_inner: Not backfilling as no backward extremeties found." + ) + return False + # If we're approaching an extremity we trigger a backfill, otherwise we # no-op. # @@ -278,47 +317,16 @@ class FederationHandler: # chose more than one times the limit in case of failure, but choosing a # much larger factor will result in triggering a backfill request much # earlier than necessary. - # - # XXX: shouldn't we do this *after* the filter by depth below? Again, we don't - # care about events that have happened after our current position. - # - max_depth = sorted_backfill_points[0].depth - if current_depth - 2 * limit > max_depth: + max_depth_of_backfill_points = sorted_backfill_points[0].depth + if current_depth - 2 * limit > max_depth_of_backfill_points: logger.debug( "Not backfilling as we don't need to. %d < %d - 2 * %d", - max_depth, + max_depth_of_backfill_points, current_depth, limit, ) return False - # We ignore extremities that have a greater depth than our current depth - # as: - # 1. we don't really care about getting events that have happened - # after our current position; and - # 2. we have likely previously tried and failed to backfill from that - # extremity, so to avoid getting "stuck" requesting the same - # backfill repeatedly we drop those extremities. - # - # However, we need to check that the filtered extremities are non-empty. - # If they are empty then either we can a) bail or b) still attempt to - # backfill. We opt to try backfilling anyway just in case we do get - # relevant events. - # - filtered_sorted_backfill_points = [ - t for t in sorted_backfill_points if t.depth <= current_depth - ] - if filtered_sorted_backfill_points: - logger.debug( - "_maybe_backfill_inner: backfill points before current depth: %s", - filtered_sorted_backfill_points, - ) - sorted_backfill_points = filtered_sorted_backfill_points - else: - logger.debug( - "_maybe_backfill_inner: all backfill points are *after* current depth. Backfilling anyway." - ) - # For performance's sake, we only want to paginate from a particular extremity # if we can actually see the events we'll get. Otherwise, we'd just spend a lot # of resources to get redacted events. We check each extremity in turn and @@ -452,10 +460,15 @@ class FederationHandler: return False - processing_end_time = self.clock.time_msec() - backfill_processing_before_timer.observe( - (processing_end_time - processing_start_time) / 1000 - ) + # If we have the `processing_start_time`, then we can make an + # observation. We wouldn't have the `processing_start_time` in the case + # where `_maybe_backfill_inner` is recursively called to find any + # backfill points regardless of `current_depth`. + if processing_start_time is not None: + processing_end_time = self.clock.time_msec() + backfill_processing_before_timer.observe( + (processing_end_time - processing_start_time) / 1000 + ) success = await try_backfill(likely_domains) if success: |