diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index a7c3d401d4..c3eecbe824 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -98,6 +98,45 @@ class StateStore(SQLBaseStore):
_get_current_state_ids_txn,
)
+ def get_state_group_delta(self, state_group):
+ """Given a state group try to return a previous group and a delta between
+ the old and the new.
+
+ Returns:
+ (prev_group, delta_ids), where both may be None.
+ """
+ def _get_state_group_delta_txn(txn):
+ prev_group = self._simple_select_one_onecol_txn(
+ txn,
+ table="state_group_edges",
+ keyvalues={
+ "state_group": state_group,
+ },
+ retcol="prev_state_group",
+ allow_none=True,
+ )
+
+ if not prev_group:
+ return None, None
+
+ delta_ids = self._simple_select_list_txn(
+ txn,
+ table="state_groups_state",
+ keyvalues={
+ "state_group": state_group,
+ },
+ retcols=("type", "state_key", "event_id",)
+ )
+
+ return prev_group, {
+ (row["type"], row["state_key"]): row["event_id"]
+ for row in delta_ids
+ }
+ return self.runInteraction(
+ "get_state_group_delta",
+ _get_state_group_delta_txn,
+ )
+
@defer.inlineCallbacks
def get_state_groups_ids(self, room_id, event_ids):
if not event_ids:
|
