diff options
Diffstat (limited to 'synapse/storage/events.py')
| -rw-r--r-- | synapse/storage/events.py | 85 |
1 files changed, 83 insertions, 2 deletions
diff --git a/synapse/storage/events.py b/synapse/storage/events.py index e791922733..919e855f3b 100644 --- a/synapse/storage/events.py +++ b/synapse/storage/events.py @@ -2052,8 +2052,10 @@ class EventsStore(StateGroupWorkerStore, EventFederationStore, EventsWorkerStore logger.info("[purge] finding state groups that can be deleted") - state_groups_to_delete, remaining_state_groups = self._find_unreferenced_groups( - txn, referenced_state_groups, + state_groups_to_delete, remaining_state_groups = ( + self._find_unreferenced_groups_during_purge( + txn, referenced_state_groups, + ) ) logger.info( @@ -2209,6 +2211,85 @@ class EventsStore(StateGroupWorkerStore, EventFederationStore, EventsWorkerStore logger.info("[purge] done") + def _find_unreferenced_groups_during_purge(self, txn, state_groups): + """Used when purging history to figure out which state groups can be + deleted and which need to be de-delta'ed (due to one of its prev groups + being scheduled for deletion). + + Args: + txn + state_groups (set[int]): Set of state groups referenced by events + that are going to be deleted. + + Returns: + tuple[set[int], set[int]]: The set of state groups that can be + deleted and the set of state groups that need to be de-delta'ed + """ + # 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 + + # Check if state groups are referenced + sql = """ + SELECT DISTINCT state_group FROM event_to_state_groups + LEFT JOIN events_to_purge AS ep USING (event_id) + WHERE state_group IN (%s) AND ep.event_id IS NULL + """ % (",".join("?" for _ in current_search),) + txn.execute(sql, list(current_search)) + + referenced = set(sg for sg, in txn) + referenced_groups |= referenced + + # We don't continue iterating up the state group graphs for state + # groups that are referenced. + current_search -= referenced + + rows = self._simple_select_many_txn( + txn, + table="state_group_edges", + column="prev_state_group", + iterable=current_search, + keyvalues={}, + retcols=("prev_state_group", "state_group",), + ) + + prevs = set(row["state_group"] for row in rows) + # We don't bother re-handling groups we've already seen + prevs -= state_groups_seen + next_to_search |= prevs + state_groups_seen |= prevs + + for row in rows: + # Note: Each state group can have at most one prev group + graph[row["state_group"]] = row["prev_state_group"] + + to_delete = state_groups_seen - referenced_groups + + to_dedelta = set() + for sg in referenced_groups: + prev_sg = graph.get(sg) + if prev_sg and prev_sg in to_delete: + to_dedelta.add(sg) + + return to_delete, to_dedelta + @defer.inlineCallbacks def is_event_after(self, event_id1, event_id2): """Returns True if event_id1 is after event_id2 in the stream |