There are scenarios where you cannot login to SQL*PLUS even with SYSDBA credentials to restart a hanged database. There is an option in sql*plus to connect, if such a scenario pop’s up.
sqlplus -prelim "/as sysdba"
SQL> shutdown abort
SQL> startup force
Another syntax to the same cmd
sqlplus /nolog
SQL> set _prelim on
SQL> conn / as sysdba
You can run hanganalyze if required before aborting the instance. That way Oracle Support can get to the depth of the problem to investigate the hanging.
