parameterApplyStatus  
  The status of parameter updates. Valid values are:
applying: The parameter group change is being applied to the database.failed-to-apply: The parameter group is in an invalid state.in-sync: The parameter group change is synchronized with the database.pending-database-upgrade: The parameter group change will be applied after the DB instance is upgraded.pending-reboot: The parameter group change will be applied after the DB instance reboots.