The Performance Advisories feature requires some privileges to connect user on monitored database.
In order to provide these privileges automatically the installer asks for another database account which has the privleges to grant the necessary privileges.
According to O7_DICTIONARY_ACCESSIBILITY database configuration parameter value
Performance Analysis GUI decides the required authentication method:
If O7_DICTIONARY_ACCESSIBILITY is TRUE, the required method is Normal authentication
If O7_DICTIONARY_ACCESSIBILITY is FALSE, the required method is SYSDBA authentication
O7_DICTIONARY_ACCESSIBILITY controls restrictions on SYSTEM privileges. If the parameter is set to TRUE (default), access to objects in SYS schema is allowed. If this parameter is set to FALSE, SYSTEM privileges that allow access to objects in other schema do not allow access to objects in dictionary schema.
O7_DICTIONARY_ACCESSIBILITY is a parameter on the database, please have the DBA to verify the value of this parameter on the monitored database.