The process for upgrading MySQL should follow the sequences outlined in Section 6.16.2, “Performing Maintenance on a Primary” whereby you would first upgrade the replicas, perform a switch and then upgrade the last remaining node.

In the majority of cases this will be sufficient, but when upgrading between major MySQL releases, there are often changes in behavior with MySQL that could either cause issues with the Tungsten Components, or with your application.

In all cases, it is paramount that your applications have been fully tested against the newer version of MySQL to ensure that your application is not impacted by any behavior changes within the core MySQL engine.

Issues that may arise, and the subsequent workarounds are outlined in the following sections of this document. Where a workaround within Tungsten is not possible, this will be clearly identified.