Overview of Oracle DB engine upgrades - Amazon Relational Database Service

Overview of Oracle DB engine upgrades

Before upgrading your Oracle DB instance, familiarize yourself with the following concepts.

Major and minor version upgrades

Amazon RDS supports the following upgrades to an Oracle DB instance:

  • Major version upgrades

    In general, a major version upgrade for a database engine can introduce changes that aren't compatible with existing applications. To upgrade your DB instance to a major version, you must perform the action manually.

  • Minor version upgrades

    A minor version upgrade includes only changes that are backward-compatible with existing applications. If you enable auto minor version upgrades on your DB instance, minor version upgrades occur automatically. In all other cases, you upgrade the DB instance manually.

When you upgrade the DB engine, an outage occurs. The duration of the outage depends on your engine version and instance size.

Oracle engine version management

With DB engine version management, you control when and how the database engine is patched and upgraded. You get the flexibility to maintain compatibility with database engine patch versions. You can also test new patch versions to ensure they work with your application before deploying them in production. In addition, you upgrade the versions on your own terms and timelines.


Amazon RDS periodically aggregates official Oracle database patches using an Amazon RDS-specific DB engine version. To see a list of which Oracle patches are contained in an Amazon RDS Oracle-specific engine version, go to Amazon RDS for Oracle Release Notes.

Automatic snapshots during engine upgrades

During upgrades of an Oracle DB instance, snapshots offer protection against upgrade issues. If the backup retention period for your DB instance is greater than 0, Amazon RDS takes the following DB snapshots during the upgrade:

  1. A snapshot of the DB instance before any upgrade changes have been made. If the upgrade fails, you can restore this snapshot to create a DB instance running the old version.

  2. A snapshot of the DB instance after the upgrade completes.


To change your backup retention period, see Modifying an Amazon RDS DB instance.

After an upgrade, you can't revert to the previous engine version. However, you can create a new Oracle DB instance by restoring the pre-upgrade snapshot.

Oracle upgrades in a Multi-AZ deployment

If your DB instance is in a Multi-AZ deployment, Amazon RDS upgrades both the primary and standby replicas. If no operating system updates are required, the primary and standby upgrades occur simultaneously. The instances are not available until the upgrade completes.

If operating system updates are required in a Multi-AZ deployment, Amazon RDS applies the updates when you request the DB upgrade. Amazon RDS performs the following steps:

  1. Updates the operating system on the standby DB instance.

  2. Upgrades the standby DB instance.

  3. Fails over the primary instance to the standby DB instance.

  4. Upgrades the operating system on the new standby DB instance, which was formerly the primary instance.

  5. Upgrades the new standby DB instance.

Oracle upgrades of read replicas

The Oracle DB engine version of the source DB instance and all of its read replicas must be the same. Amazon RDS performs the upgrade in the following stages:

  1. Upgrades the source DB instance. The read replicas are available during this stage.

  2. Upgrades the read replicas in parallel, regardless of the replica maintenance windows. The source DB is available during this stage.

For major version upgrades of cross-Region read replicas, Amazon RDS performs additional actions:

  • Generates an option group for the target version automatically

  • Copies all options and option settings from the original option group to the new option group

  • Associates the upgraded cross-Region read replica with the new option group

Oracle upgrades of micro DB instances

We don't recommend upgrading databases running on micro DB instances. Because these instances have limited CPU, the upgrade can take hours to complete.

You can upgrade micro DB instances with small amounts of storage (10–20 GiB) by copying your data using Data Pump. Before you migrate your production DB instances, we recommend that you test by copying data using Data Pump.