From 2d1d7b7e6f2bec3b96b0d23993369ce46aad4f32 Mon Sep 17 00:00:00 2001 From: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com> Date: Thu, 6 Jun 2019 23:54:00 +0100 Subject: Prevent multiple device list updates from breaking a batch send (#5156) fixes #5153 --- synapse/storage/devices.py | 152 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 123 insertions(+), 29 deletions(-) (limited to 'synapse/storage') diff --git a/synapse/storage/devices.py b/synapse/storage/devices.py index fd869b934c..d102e07372 100644 --- a/synapse/storage/devices.py +++ b/synapse/storage/devices.py @@ -14,7 +14,7 @@ # limitations under the License. import logging -from six import iteritems, itervalues +from six import iteritems from canonicaljson import json @@ -72,11 +72,14 @@ class DeviceWorkerStore(SQLBaseStore): defer.returnValue({d["device_id"]: d for d in devices}) - def get_devices_by_remote(self, destination, from_stream_id): + @defer.inlineCallbacks + def get_devices_by_remote(self, destination, from_stream_id, limit): """Get stream of updates to send to remote servers Returns: - (int, list[dict]): current stream id and list of updates + Deferred[tuple[int, list[dict]]]: + current stream id (ie, the stream id of the last update included in the + response), and the list of updates """ now_stream_id = self._device_list_id_gen.get_current_token() @@ -84,55 +87,131 @@ class DeviceWorkerStore(SQLBaseStore): destination, int(from_stream_id) ) if not has_changed: - return (now_stream_id, []) - - return self.runInteraction( + defer.returnValue((now_stream_id, [])) + + # We retrieve n+1 devices from the list of outbound pokes where n is + # our outbound device update limit. We then check if the very last + # device has the same stream_id as the second-to-last device. If so, + # then we ignore all devices with that stream_id and only send the + # devices with a lower stream_id. + # + # If when culling the list we end up with no devices afterwards, we + # consider the device update to be too large, and simply skip the + # stream_id; the rationale being that such a large device list update + # is likely an error. + updates = yield self.runInteraction( "get_devices_by_remote", self._get_devices_by_remote_txn, destination, from_stream_id, now_stream_id, + limit + 1, ) + # Return an empty list if there are no updates + if not updates: + defer.returnValue((now_stream_id, [])) + + # if we have exceeded the limit, we need to exclude any results with the + # same stream_id as the last row. + if len(updates) > limit: + stream_id_cutoff = updates[-1][2] + now_stream_id = stream_id_cutoff - 1 + else: + stream_id_cutoff = None + + # Perform the equivalent of a GROUP BY + # + # Iterate through the updates list and copy non-duplicate + # (user_id, device_id) entries into a map, with the value being + # the max stream_id across each set of duplicate entries + # + # maps (user_id, device_id) -> stream_id + # as long as their stream_id does not match that of the last row + query_map = {} + for update in updates: + if stream_id_cutoff is not None and update[2] >= stream_id_cutoff: + # Stop processing updates + break + + key = (update[0], update[1]) + query_map[key] = max(query_map.get(key, 0), update[2]) + + # If we didn't find any updates with a stream_id lower than the cutoff, it + # means that there are more than limit updates all of which have the same + # steam_id. + + # That should only happen if a client is spamming the server with new + # devices, in which case E2E isn't going to work well anyway. We'll just + # skip that stream_id and return an empty list, and continue with the next + # stream_id next time. + if not query_map: + defer.returnValue((stream_id_cutoff, [])) + + results = yield self._get_device_update_edus_by_remote( + destination, + from_stream_id, + query_map, + ) + + defer.returnValue((now_stream_id, results)) + def _get_devices_by_remote_txn( - self, txn, destination, from_stream_id, now_stream_id + self, txn, destination, from_stream_id, now_stream_id, limit ): + """Return device update information for a given remote destination + + Args: + txn (LoggingTransaction): The transaction to execute + destination (str): The host the device updates are intended for + from_stream_id (int): The minimum stream_id to filter updates by, exclusive + now_stream_id (int): The maximum stream_id to filter updates by, inclusive + limit (int): Maximum number of device updates to return + + Returns: + List: List of device updates + """ sql = """ - SELECT user_id, device_id, max(stream_id) FROM device_lists_outbound_pokes + SELECT user_id, device_id, stream_id FROM device_lists_outbound_pokes WHERE destination = ? AND ? < stream_id AND stream_id <= ? AND sent = ? - GROUP BY user_id, device_id - LIMIT 20 + ORDER BY stream_id + LIMIT ? """ - txn.execute(sql, (destination, from_stream_id, now_stream_id, False)) + txn.execute(sql, (destination, from_stream_id, now_stream_id, False, limit)) - # maps (user_id, device_id) -> stream_id - query_map = {(r[0], r[1]): r[2] for r in txn} - if not query_map: - return (now_stream_id, []) + return list(txn) - if len(query_map) >= 20: - now_stream_id = max(stream_id for stream_id in itervalues(query_map)) + @defer.inlineCallbacks + def _get_device_update_edus_by_remote( + self, destination, from_stream_id, query_map, + ): + """Returns a list of device update EDUs as well as E2EE keys - devices = self._get_e2e_device_keys_txn( - txn, + Args: + destination (str): The host the device updates are intended for + from_stream_id (int): The minimum stream_id to filter updates by, exclusive + query_map (Dict[(str, str): int]): Dictionary mapping + user_id/device_id to update stream_id + + Returns: + List[Dict]: List of objects representing an device update EDU + + """ + devices = yield self.runInteraction( + "_get_e2e_device_keys_txn", + self._get_e2e_device_keys_txn, query_map.keys(), include_all_devices=True, include_deleted_devices=True, ) - prev_sent_id_sql = """ - SELECT coalesce(max(stream_id), 0) as stream_id - FROM device_lists_outbound_last_success - WHERE destination = ? AND user_id = ? AND stream_id <= ? - """ - results = [] for user_id, user_devices in iteritems(devices): # The prev_id for the first row is always the last row before # `from_stream_id` - txn.execute(prev_sent_id_sql, (destination, user_id, from_stream_id)) - rows = txn.fetchall() - prev_id = rows[0][0] + prev_id = yield self._get_last_device_update_for_remote_user( + destination, user_id, from_stream_id, + ) for device_id, device in iteritems(user_devices): stream_id = query_map[(user_id, device_id)] result = { @@ -156,7 +235,22 @@ class DeviceWorkerStore(SQLBaseStore): results.append(result) - return (now_stream_id, results) + defer.returnValue(results) + + def _get_last_device_update_for_remote_user( + self, destination, user_id, from_stream_id, + ): + def f(txn): + prev_sent_id_sql = """ + SELECT coalesce(max(stream_id), 0) as stream_id + FROM device_lists_outbound_last_success + WHERE destination = ? AND user_id = ? AND stream_id <= ? + """ + txn.execute(prev_sent_id_sql, (destination, user_id, from_stream_id)) + rows = txn.fetchall() + return rows[0][0] + + return self.runInteraction("get_last_device_update_for_remote_user", f) def mark_as_sent_devices_by_remote(self, destination, stream_id): """Mark that updates have successfully been sent to the destination. -- cgit 1.4.1