Oracle major version upgrades

To perform a major version upgrade, modify the DB instance manually. Major version upgrades don't occur automatically.

Supported versions for major upgrades

Amazon RDS supports the following major version upgrades.

A major version upgrade of Oracle Database must upgrade to a Release Update (RU) that was released in the same month or later. Major version downgrades aren't supported for any Oracle Database versions.

Supported instance classes for major upgrades

Your current Oracle DB instance might run on a DB instance class that isn't supported for the version to which you are upgrading. In this case, before you upgrade, migrate the DB instance to a supported DB instance class. For more information about the supported DB instance classes for each version and edition of Amazon RDS for Oracle, see DB instance classes.

Gathering statistics before major upgrades

Before you perform a major version upgrade, Oracle recommends that you gather optimizer statistics on the DB instance that you are upgrading. This action can reduce DB instance downtime during the upgrade.

To gather optimizer statistics, connect to the DB instance as the master user, and run the DBMS_STATS.GATHER_DICTIONARY_STATS procedure, as in the following example.

EXEC DBMS_STATS.GATHER_DICTIONARY_STATS;

For more information, see GATHER_DICTIONARY_STATS Procedure in the Oracle documentation.

Allowing major upgrades

A major engine version upgrade might be incompatible with your application. The upgrade is irreversible. If you specify a major version for the EngineVersion parameter that is different from the current major version, you must allow major version upgrades.

If you upgrade a major version using the CLI command modify-db-instance, specify --allow-major-version-upgrade. This setting isn't persistent, so you must specify --allow-major-version-upgrade whenever you perform a major upgrade. This parameter has no impact on upgrades of minor engine versions. For more information, see Upgrading a DB instance engine version.

If you upgrade a major version using the console, you don't need to choose an option to allow the upgrade. Instead, the console displays a warning that major upgrades are irreversible.