By default, Oracle BI Presentation Services is configured to log all error events and informational and warning events of sufficient importance.
An example of an important informational event is a server starting up or a server shutting down. Log files are named sawlogxx.log, where the xx is replaced by an incremented number.
The sawlog0 file is located:
You can query this log file online. See WebLogic - Diagnostics Framework (WLDF)