From a2f6d31a63012531935566e380dfb5edd81dcbd0 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Wed, 26 Jun 2019 11:56:52 +0100 Subject: [PATCH] Refactor get_user_ids_changed to pull less from DB When a client asks for users whose devices have changed since a token we used to pull *all* users from the database since the token, which could easily be thousands of rows for old tokens. This PR changes this to only check for changes for users the client is actually interested in. Fixes #5553 --- synapse/handlers/device.py | 12 ++++----- synapse/handlers/sync.py | 24 ++++++++---------- synapse/storage/devices.py | 51 ++++++++++++++++++++++++++++++-------- 3 files changed, 58 insertions(+), 29 deletions(-) diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py index f59d0479b..2b6c2117f 100644 --- a/synapse/handlers/device.py +++ b/synapse/handlers/device.py @@ -101,9 +101,13 @@ class DeviceWorkerHandler(BaseHandler): room_ids = yield self.store.get_rooms_for_user(user_id) - # First we check if any devices have changed + # First we check if any devices have changed for users that we share + # rooms with. + users_who_share_room = yield self.store.get_users_who_share_room_with_user( + user_id + ) changed = yield self.store.get_user_whose_devices_changed( - from_token.device_list_key + from_token.device_list_key, users_who_share_room ) # Then work out if any users have since joined @@ -188,10 +192,6 @@ class DeviceWorkerHandler(BaseHandler): break if possibly_changed or possibly_left: - users_who_share_room = yield self.store.get_users_who_share_room_with_user( - user_id - ) - # Take the intersection of the users whose devices may have changed # and those that actually still share a room with the user possibly_joined = possibly_changed & users_who_share_room diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py index c5188a1f8..8249e75ec 100644 --- a/synapse/handlers/sync.py +++ b/synapse/handlers/sync.py @@ -1062,10 +1062,6 @@ class SyncHandler(object): since_token = sync_result_builder.since_token if since_token and since_token.device_list_key: - changed = yield self.store.get_user_whose_devices_changed( - since_token.device_list_key - ) - # TODO: Be more clever than this, i.e. remove users who we already # share a room with? for room_id in newly_joined_rooms: @@ -1076,21 +1072,23 @@ class SyncHandler(object): left_users = yield self.state.get_current_users_in_room(room_id) newly_left_users.update(left_users) - # TODO: Check that these users are actually new, i.e. either they - # weren't in the previous sync *or* they left and rejoined. - changed.update(newly_joined_or_invited_users) - - if not changed and not newly_left_users: - defer.returnValue(DeviceLists(changed=[], left=newly_left_users)) - users_who_share_room = yield self.store.get_users_who_share_room_with_user( user_id ) + # TODO: Check that these users are actually new, i.e. either they + # weren't in the previous sync *or* they left and rejoined. + changed = users_who_share_room & set(newly_joined_or_invited_users) + + changed_users = yield self.store.get_user_whose_devices_changed( + since_token.device_list_key, users_who_share_room + ) + + changed.update(changed_users) + defer.returnValue( DeviceLists( - changed=users_who_share_room & changed, - left=set(newly_left_users) - users_who_share_room, + changed=changed, left=set(newly_left_users) - users_who_share_room ) ) else: diff --git a/synapse/storage/devices.py b/synapse/storage/devices.py index 3413a4667..3af0171f7 100644 --- a/synapse/storage/devices.py +++ b/synapse/storage/devices.py @@ -391,22 +391,53 @@ class DeviceWorkerStore(SQLBaseStore): return now_stream_id, [] - @defer.inlineCallbacks - def get_user_whose_devices_changed(self, from_key): - """Get set of users whose devices have changed since `from_key`. + def get_user_whose_devices_changed(self, from_key, user_ids): + """Get set of users whose devices have changed since `from_key` that + are in the given list of user_ids. + + Args: + user_ids (Iterable[str]) + from_key: The device lists stream token + + Returns: + Deferred[set[str]]: The set of user_ids whose devices have changed + since `from_key` """ from_key = int(from_key) - changed = self._device_list_stream_cache.get_all_entities_changed(from_key) - if changed is not None: - defer.returnValue(set(changed)) + + # Get set of users who *may* have changed. Users not in the returned + # list have definitely not changed. + to_check = list( + self._device_list_stream_cache.get_entities_changed(user_ids, from_key) + ) + + if not to_check: + return defer.succeed(set()) + + # We now check the database for all users in `to_check`, in batches. + batch_size = 100 + chunks = [ + to_check[i : i + batch_size] for i in range(0, len(to_check), batch_size) + ] sql = """ - SELECT DISTINCT user_id FROM device_lists_stream WHERE stream_id > ? + SELECT DISTINCT user_id FROM device_lists_stream + WHERE stream_id > ? + AND user_id IN (%s) """ - rows = yield self._execute( - "get_user_whose_devices_changed", None, sql, from_key + + def _get_user_whose_devices_changed_txn(txn): + changes = set() + + for chunk in chunks: + txn.execute(sql % (",".join("?" for _ in chunk),), [from_key] + chunk) + changes.update(user_id for user_id, in txn) + + return changes + + return self.runInteraction( + "get_user_whose_devices_changed", _get_user_whose_devices_changed_txn ) - defer.returnValue(set(row[0] for row in rows)) def get_all_device_list_changes_for_remotes(self, from_key, to_key): """Return a list of `(stream_id, user_id, destination)` which is the