HeatWave: Single-AD HeatWave cluster optimization when changing the primary instance of a high availability DB system

Previously, in a high availability DB system with HeatWave cluster enabled, a change in the current placement of the primary instance due to a switchover, failover, upgrade, or scheduled maintenance causes the HeatWave cluster to be deleted and recreated.

This has now been optimized when the DB system is located in a single-AD region or is connected to an AD-specific subnet in a region with multiple ADs, the HeatWave cluster is detached from the previous primary instance and reattached to the new primary instance in the same AD. However, when the previous primary instance and the new primary instance are located in different ADs, the HeatWave cluster still need to be deleted and recreated because the HeatWave cluster must be located in the same AD as the primary instance of the DB system.

For more information, see Overview of High Availability - HeatWave Cluster Support.