About the Tuning Log
Database Engine Tuning Advisor writes to a table all the relevant information and error messages about events in a workload that Database Engine Tuning Advisor could not tune during any given tuning session. The tuning log is designed so that the messages are categorized and can easily be searched. The recommended way to view the tuning log is by using the Database Engine Tuning Advisor graphical user interface (GUI). For information about using this tool to view the tuning logs, see How to: View Tuning Output.
The tuning log records messages about statements in the workload that cannot be tuned for the following reasons:
Statement does not reference any table.
Statement references a table that does not exist.
Statement is not tuned because tuning it would increase the query cost.
For more details about the tuning log table and the information contained in its columns, see Errors and Messages.