How do you tune SQL if you don't have access to the source code? Sometimes Oracle indexes, statistics, stored outlines, profiles or 12c directives will solve a tuning problem. However, as a last resort, you may want to add a hint. In this case DBMS_ADVANCED_REWRITE could be the solution. In this tutorial, Oracle Certified Master DBA John Watson of SkillBuilders demonstrates using DBMS_ADVANCED_REWRITE to change the SQL Oracle executes - without changing the source code!