diff options
Diffstat (limited to 'synapse/storage')
| -rw-r--r-- | synapse/storage/events.py | 33 | ||||
| -rw-r--r-- | synapse/storage/state.py | 50 |
2 files changed, 77 insertions, 6 deletions
diff --git a/synapse/storage/events.py b/synapse/storage/events.py index e7487311ce..0fb190530a 100644 --- a/synapse/storage/events.py +++ b/synapse/storage/events.py @@ -2025,6 +2025,7 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore logger.info("[purge] finding state groups which depend on redundant" " state groups") remaining_state_groups = [] + unreferenced_state_groups = 0 for i in range(0, len(state_rows), 100): chunk = [sg for sg, in state_rows[i:i + 100]] # look for state groups whose prev_state_group is one we are about @@ -2037,13 +2038,33 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore retcols=["state_group"], keyvalues={}, ) - remaining_state_groups.extend( - row["state_group"] for row in rows - # exclude state groups we are about to delete: no point in - # updating them - if row["state_group"] not in state_groups_to_delete - ) + for row in rows: + sg = row["state_group"] + + if sg in state_groups_to_delete: + # exclude state groups we are about to delete: no point in + # updating them + continue + + if not self._is_state_group_referenced(txn, sg): + # Let's also delete unreferenced state groups while we're + # here, since otherwise we'd need to de-delta them + state_groups_to_delete.add(sg) + unreferenced_state_groups += 1 + continue + + remaining_state_groups.append(sg) + + logger.info( + "[purge] found %i extra unreferenced state groups to delete", + unreferenced_state_groups, + ) + + logger.info( + "[purge] de-delta-ing %i remaining state groups", + len(remaining_state_groups), + ) # Now we turn the state groups that reference to-be-deleted state # groups to non delta versions. diff --git a/synapse/storage/state.py b/synapse/storage/state.py index 3f4cbd61c4..b88c7dc091 100644 --- a/synapse/storage/state.py +++ b/synapse/storage/state.py @@ -1041,6 +1041,56 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore): return count + def _is_state_group_referenced(self, txn, state_group): + """Checks if a given state group is referenced, or is safe to delete. + + A state groups is referenced if it or any of its descendants are + pointed at by an event. (A descendant is a group which has the given + state_group as a prev group) + """ + + # We check this by doing a depth first search to look for any + # descendant referenced by `event_to_state_groups`. + + # State groups we need to check, contains state groups that are + # descendants of `state_group` + state_groups_to_search = [state_group] + + # Set of state groups we've already checked + state_groups_searched = set() + + while state_groups_to_search: + state_group = state_groups_to_search.pop() # Next state group to check + + is_referenced = self._simple_select_one_onecol_txn( + txn, + table="event_to_state_groups", + keyvalues={"state_group": state_group}, + retcol="event_id", + allow_none=True, + ) + if is_referenced: + # A descendant is referenced by event_to_state_groups, so + # original state group is referenced. + return True + + state_groups_searched.add(state_group) + + # Find all children of current state group and add to search + references = self._simple_select_onecol_txn( + txn, + table="state_group_edges", + keyvalues={"prev_state_group": state_group}, + retcol="state_group", + ) + state_groups_to_search.extend(references) + + # Lets be paranoid and check for cycles + if state_groups_searched.intersection(references): + raise Exception("State group %s has cyclic dependency", state_group) + + return False + class StateStore(StateGroupWorkerStore, BackgroundUpdateStore): """ Keeps track of the state at a given event. |