diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index dfec57c045..d737bd6778 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -1234,85 +1234,6 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
return count
- def _find_unreferenced_groups(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(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
-
class StateStore(StateGroupWorkerStore, BackgroundUpdateStore):
""" Keeps track of the state at a given event.
|
