A few Tips To Save The Database Statistics

For baselines and reference: export AWR
        ~rdbms/admin/awrextr.sql
        ~rdbms/admin/awrload.sql

 For diagnostics: always get AWR and ASH reports
        ~rdbms/admin/ashrpt
        ~rdbms/admin/awrrpt

 For emergencies and “last gasp”: get ASH dump(*)
         oradebug ashdump