Correctly delete old state groups in purge history API

1 files changed, 1 insertions, 0 deletions

diff --git a/synapse/storage/schema/delta/35/state.sql b/synapse/storage/schema/delta/35/state.sql

index c4c244c169..0f1fa68a89 100644
--- a/synapse/storage/schema/delta/35/state.sql
+++ b/synapse/storage/schema/delta/35/state.sql
@@ -19,3 +19,4 @@ CREATE TABLE state_group_edges(
 );
 
 CREATE INDEX state_group_edges_idx ON state_group_edges(state_group);
+CREATE INDEX state_group_edges_prev_idx ON state_group_edges(prev_state_group);