You are always responsible to check if the following steps are suitable for your situation. Always check the Upgrade Guide or consult Oracle Support.
This is how I manually upgraded a simple Dev database from 10.2 to 12.1 (no multi-tenant)
- Run the <12c-home>/rdbms/admin/preupgrd.sql on the old database.12c-home>
- Check the $ORACLE_BASE/cfgtoollogs/
/preupgrade/preupgrade.log and fix whatever needs to be fixed
- Re-run preupgrd.sql to check after fixing.
- Shutdown old database.
- Move all datafiles, controlfiles, redologfiles etc to new host
- Move the init
.ora to new host.
- Make changes in init
.ora following preupgrade.log
- Create directories for e.g. audit_dump_dest
- SQL> startup Upgrade
- Go to OS prompt, cd $ORACLE_HOME/rdbms/admin
- $ORACLE_HOME/perl/bin/perl catctl.pl catupgrd.sql (takes about 30-40mins)
- SQL> startup
- SQL> @?/rdbms/admin/utlrp (to repair invalid objects)
- SQL> @?/rdbms/admin/utlu121s.sql (to check status of components, should show VALID only)
- Backup database