Ensure txn is rolled back if not committed

listener.go

diff --git a/listener.go b/listener.go
index 7dcd4b6..0837149 100644
--- a/listener.go
+++ b/listener.go
@@ -470,6 +470,7 @@
 		log.Error("Unable to create transaction")
 		return
 	}
+	defer txn.Rollback()
 
 	var rows []common.Row
 	ok := true