Query: target_ro_rds_db_instances_for_rds_instance

select
  related_instances.arn as db_instance_arn
from
  alicloud_rds_instance as self,
  alicloud_rds_instance as related_instances
where
  self.arn = $1
  and self.account_id = split_part($1,':',5)
  and self.region = split_part($1,':',4)
  and (related_instances.master_instance_id = self.db_instance_id or self.master_instance_id = related_instances.db_instance_id)