Automatic Database Diagnostic Monitor(ADDM) can analyze performance issues during a particular period and provide suggestion. An ADDM analysis is performed on a set of awr snapshots. addmrpt.sql script is used to generate addm report.

Generate ADDM report:

cd $ORACLE_HOME/rdbms/admin

SQL> @addmrpt.sql

It will ask for begin snap_id and end snap_id

Privileges required for non-sys users to generate addm report:

From 12c onward, awr report contains addm output also