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Diffstat (limited to 'synapse/storage/purge_events.py')
| -rw-r--r-- | synapse/storage/purge_events.py | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/synapse/storage/purge_events.py b/synapse/storage/purge_events.py new file mode 100644 index 0000000000..fdc0abf5cf --- /dev/null +++ b/synapse/storage/purge_events.py @@ -0,0 +1,117 @@ +# -*- coding: utf-8 -*- +# Copyright 2019 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. + +import itertools +import logging + +from twisted.internet import defer + +logger = logging.getLogger(__name__) + + +class PurgeEventsStorage(object): + """High level interface for purging rooms and event history. + """ + + def __init__(self, hs, stores): + self.stores = stores + + @defer.inlineCallbacks + def purge_room(self, room_id: str): + """Deletes all record of a room + """ + + state_groups_to_delete = yield self.stores.main.purge_room(room_id) + yield self.stores.state.purge_room_state(room_id, state_groups_to_delete) + + @defer.inlineCallbacks + def purge_history(self, room_id, token, delete_local_events): + """Deletes room history before a certain point + + Args: + room_id (str): + + token (str): A topological token to delete events before + + delete_local_events (bool): + if True, we will delete local events as well as remote ones + (instead of just marking them as outliers and deleting their + state groups). + """ + state_groups = yield self.stores.main.purge_history( + room_id, token, delete_local_events + ) + + logger.info("[purge] finding state groups that can be deleted") + + sg_to_delete = yield self._find_unreferenced_groups(state_groups) + + yield self.stores.state.purge_unreferenced_state_groups(room_id, sg_to_delete) + + @defer.inlineCallbacks + def _find_unreferenced_groups(self, state_groups): + """Used when purging history to figure out which state groups can be + deleted. + + Args: + state_groups (set[int]): Set of state groups referenced by events + that are going to be deleted. + + Returns: + Deferred[set[int]] The set of state groups that can be deleted. + """ + # Graph of state group -> previous group + graph = {} + + # Set of events that we have found to be referenced by events + referenced_groups = set() + + # Set of state groups we've already seen + state_groups_seen = set(state_groups) + + # Set of state groups to handle next. + next_to_search = set(state_groups) + while next_to_search: + # We bound size of groups we're looking up at once, to stop the + # SQL query getting too big + if len(next_to_search) < 100: + current_search = next_to_search + next_to_search = set() + else: + current_search = set(itertools.islice(next_to_search, 100)) + next_to_search -= current_search + + referenced = yield self.stores.main.get_referenced_state_groups( + current_search + ) + referenced_groups |= referenced + + # We don't continue iterating up the state group graphs for state + # groups that are referenced. + current_search -= referenced + + edges = yield self.stores.state.get_previous_state_groups(current_search) + + prevs = set(edges.values()) + # We don't bother re-handling groups we've already seen + prevs -= state_groups_seen + next_to_search |= prevs + state_groups_seen |= prevs + + graph.update(edges) + + to_delete = state_groups_seen - referenced_groups + + return to_delete |