1. Preupgrade Utility
Preupgrade utility “utlu121s.sql” is replaced with “preupgrd.sql”. The new utility provides fixup scripts “preupgrade_fixups.sql” and “postupggrade_fixups.sql” to address issues that might be present both before and after the upgrade.These fixup scripts can be executed interactively.
2. Upgrade Utility
The catupgrd.sql Upgrade utility is replaced with the catctl.pl utility. The new utility allows you to take advantage of CPUs by running the upgrade process in parallel thereby reducing the upgrade time. This new script is used more like a wrapper on the existing one. Also by default “catuppst.sql” is run when “catctl.pl” is executed. The new script has lot of options , few of them are explained below.
Option “-n” specifies the degree of parallelism, the default is 4 and maximum is 8.
Option “-p” supports rerun of the upgrade by skipping successful steps.
Example: $ORACLE_HOME/perl/bin/perl catctl.pl -n 6 -p $ORACLE_HOME/rdbms/admin/catupgrd.sql
3. XML DB
Oracle XML DB is no longer an optional component and therefore cannot be uninstalled. It is automatically installed into SYSAUX tablespace when you create a new 12c database or if you upgrade from prior versions of Oracle.
4. Upgrade Status
A successful upgrade sets the status of database status to UPGRADED. This is different from previous versions where the status is set to VALID. The database status is set to VALID only if ultrp.sql is executed.