Oracle major version upgrades - Amazon Relational Database Service
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Oracle major version upgrades

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

Important

Make sure that you thoroughly test any upgrade to verify that your applications work correctly before applying the upgrade to your production databases. For more information, see Testing an Oracle DB upgrade.

Supported versions for major upgrades

Amazon RDS supports the following major version upgrades.

Note

Oracle Database 26ai is available only in Enterprise Edition.

Current version Upgrade supported

21.0.0.0 using the CDB architecture

26.0.0.0

19.0.0.0 using the CDB architecture

21.0.0.0, 26.0.0.0

Note

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. For more information about the Oracle Database versions that Amazon RDS supports, see the Amazon RDS for Oracle Release Notes.

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.

Upgrading to Oracle Database 26ai

You can perform a major version upgrade to Oracle Database 26ai (26.0.0.0) from the following source versions:

  • Oracle Database 21c using the CDB architecture

  • Oracle Database 19c using the CDB architecture

Oracle Database 26ai supports only the CDB architecture. If your DB instance runs Oracle Database 19c as a non-CDB, first convert it to a CDB, and then upgrade it to Oracle Database 26ai. You can't change the database architecture during an upgrade. For more information, see Converting an RDS for Oracle non-CDB to a CDB.

After you convert a non-CDB to a CDB, the database uses the single-tenant configuration. To add tenant databases (PDBs), convert the database from the single-tenant configuration to the multi-tenant configuration. For more information, see Converting the single-tenant configuration to multi-tenant.

Before you upgrade to Oracle Database 26ai, review the following changes: