You want to upgrade an Oracle Database running Oracle Database 11g to Oracle Database 12c. Which three tasks should be performed before a manual upgrade?

Running preupgrd.sql from the source Oracle 11g home analyzes the existing database and generates fix-up scripts that resolve pre-upgrade issues automatically. It also produces a log file that summarizes required manual actions, deprecated parameters, and any components that need attention before the upgrade begins.

The pre-upgrade utility must be executed from the source Oracle 11g home against the existing database, not from the new Oracle 12c home, because it needs to inspect the current database state and version-specific objects.

The initialization parameter file (init.ora or spfile) must be present in the new Oracle 12c home so the upgraded instance can read its configuration during startup. Copying it before the upgrade ensures the new Oracle home has the correct settings and avoids startup failures post-upgrade.

In Oracle 12c the password file format changed to support longer user names and case-sensitive passwords, so the old 11g password file should not simply be copied - a new one should be created in the new Oracle home using orapwd.

Net configuration files such as listener.ora and tnsnames.ora must be copied to the new Oracle home so that network connectivity and remote client access are maintained after the upgrade. Without them, the listener in the new home would have no knowledge of the database service or connection descriptors.