The logging levels are set to specify the events and messages to record in the log file or in the log database. A different logging level can be set for each dispatcher service.
In Cognos 8 there are 5 different logging levels: Minimal, Basic, Request, Trace, Full.

Attached below is a list of logging events by a level:

System and service startup and shutdown, runtime errors - logged on all 5 levels

User account management, runtime usage of IBM Cognos 8, use requests - Basic, Request, Trace, Full (all except Minimal)

Service requests and responses - Request, Full

All requests to all components with parameter values, native queries - Trace, Full