Upgradation from Oracle 12c to Oracle 19c use DBUA utility

Pre-check:

Ensure backup is complete before upgrade.

SQL> SELECT * FROM v$backup WHERE status != 'NOT ACTIVE';

Empty Recycle bin.

SQL> PURGE DBA_RECYCLEBIN ;

Run Gather statistics to finish upgrade soon.

SQL> EXEC DBMS_STATS.GATHER_DICTIONARY_STATS;

Step 1: Stop the Listener and run the preupgrade tool

java -jar /u01/app/oracle/product/19.0.0/dbhome_1/rdbms/admin/preupgrade.jar TEXT TERMINAL

We get:

/u01/app/oracle/cfgtoollogs/upgr/preupgrade/preupgrade.log
/u01/app/oracle/cfgtoollogs/upgr/preupgrade/preupgrade_fixups.sql
/u01/app/oracle/cfgtoollogs/upgr/preupgrade/postupgrade_fixups.sql

Step 2: Run the preupgrade fixups

@/u01/app/oracle/cfgtoollogs/upgr/preupgrade/preupgrade_fixups.sql

Step 3:Run DBUA tool

$ export ORACLE_HOME=/u01/app/oracle/product/19.0.0/dbhome_1
$ export ORACLE_SID=upgr
$ export PATH=$ORACLE_HOME/bin:$PATH
$ dbua

Step 4: run the Postupgrade fixups

@/u01/app/oracle/cfgtoollogs/upgr/preupgrade/postupgrade_fixups.sql

Step 5: check version

select VERSION,name,open_mode from v$instance,v$database;