Given a txid, get all subdomain operations at that txid.
        Include unaccepted operations.
        Order by zone file index

def get_subdomain_ops_at_txid(self, txid, cur=None):
        """
        Given a txid, get all subdomain operations at that txid.
        Include unaccepted operations.
        Order by zone file index
        """
        get_cmd = 'SELECT * FROM {} WHERE txid = ? ORDER BY zonefile_offset'.format(self.subdomain_table)

        cursor = None
        if cur is None:
            cursor = self.conn.cursor()
        else:
            cursor = cur

        db_query_execute(cursor, get_cmd, (txid,))

        try:
            return [x for x in cursor.fetchall()]
        except Exception as e:
            if BLOCKSTACK_DEBUG:
                log.exception(e)

            return []