Oracle Trouble Shooting Startup Hang

$ truss -Daefo /tmp/startup.txt sqlplus / as sysdba
SQL> startup mount
SQL> alter session set tracefile_identifier='10046';
SQL> Alter session set timed_statistics = true;
SQL> Alter session set statistics_level=all;
SQL> Alter session set max_dump_file_size = unlimited;
SQL> Alter session set events '10046 trace name context forever, level 12';

SQL> alter database open;
-- Wait 5-10 minutes then kill process and shutdown immediate


+++

Please collect the Hanganalyse report from another session to identify the blocking chains

SQL> sqlplus " / as sysdba"
SQL> oradebug setmypid
SQL> oradebug unlimit
SQL> oradebug hanganalyze 3
-- wait 90 seconds
SQL> oradebug hanganalyze 3
SQL> oradebug tracefile_name
SQL> exit



++ Upload the startup.txt , 10046 trace file and Hang analyze