The Error Log Event Type Numeric Priority Error event 1 Warning event 2 Note/information event 3 The  prio  value is numeric. Related to it, an error event may also include an optional  label  field representing the priority as a string. For example, an event with a  prio  value of 2 may have a  label value of  ’Warning’ . Filter components may include or drop error events based on priority, except that system events are mandatory and cannot be dropped. In general, message priorities are determined as follows: Is the situation or event actionable? •Yes: Is the situation or event ignorable? •Yes: Priority is warning. •No: Priority is error. •No: Is the situation or event mandatory? •Yes: Priority is system. •No: Priority is note/information. • err_code • err_symbol • SQL_state • subsystem The event error code, as a number (for example,  1022 ). The event error symbol, as a string (for example,  ’ER_DUP_KEY’ ). The event SQLSTATE value, as a string (for example,  ’23000’ ). The subsystem in which the event occurred. Possible values are  InnoDB  (the  InnoDB  storage engine), Repl  (the replication subsystem),  Server  (otherwise). Optional error event fields fall into the following categories: The operating system error number. •Additional information about the error, such as the error signaled by the operating system or the error lable: • OS_errno • OS_errmsg Optional Error Event Fields 1031