Database Time (DB Time) is the primary measure used for Oracle database performance tuning.  Average Active Sessions (AAS) measures the rate at which DB Time is accumulating in an Oracle system. These two fundamental concepts are at the heart of the DB Time Method for optimizing database performance, at both system and individual query levels. The presentation will clearly explain DB Time and AAS as well as how tools like ADDM Spotlight, Perf Hub, ASH and AWR are designed to assist DBAs optimizing performance using the DB Time Method.