Incident logs were introduced in 11g. When a critical error happens (e.g. system crashes) an incident is generated and this event is recorded in the alert and trace logs. The incident log is similar to the trace log (meaning that is not well formatted).
Devo will allow you to search for existing incidents, monitor critical incidents, send out alerts, and take actions.
The table below provides the default location for the log file and the query you can run in case location has changed.
|Log format||Oracle version||Tags||Default file location|
|Plain text||11g/12c (Linux and Windows)|
select value from v$diag_info where name = 'Diag Incident';