Additional uncaught exception thrown while handling exception.

Original

PDOException: SQLSTATE[08004] [1040] Too many connections in lock_may_be_available() (line 167 of /usr/local/www/vhosts/riotinto_drupal/includes/lock.inc).

Additional

PDOException: SQLSTATE[08004] [1040] Too many connections in system_list() (line 165 of /usr/local/www/vhosts/riotinto_drupal/includes/module.inc).