MySQL Engine Upgrades

Tessell provides newer versions of the MySQL database engine to ensure your DB instances remain secure, stable, and up to date. Engine upgrades may include:

• Security patches

• Bug fixes

• Performance improvements

• Stability enhancements

• Feature updates

There are two types of upgrades in MySQL database engine:

• Minor Version Upgrades

• Major Version Upgrades

For more information about supported MySQL versions in Tessell, see MySQL Support Matrix.

Minor Version Upgrades

A minor version upgrade applies changes that are backward-compatible with existing applications.

Example:

• Upgrading from MySQL 8.0.32 to 8.0.40 version

• Upgrading from MySQL 8.4.5 to 8.4.6 version

You can perform minor version upgrades directly through the Tessell Console. The service downtime depends upon the deployment type and database recovery time.

For Single-AZ deployments, Tessell stops mysql service on single-az instance, applies the patch and then restarts the mysql service. The typical downtime would be 2-10 min and it can be longer if there are large transactions or lengthy db recovery processes.

For Multi-AZ deployments, Tessell performs rolling upgrades to minimize downtime and the typical downtime is 60-120 seconds during a switchover. This rolling approach ensures minimal service interruption.

1. Upgrade begins with the HA replica instances one at a time.

2. One of the upgraded HA replica(s) is promoted as Primary.

3. The original Primary (which is now a replica) is upgraded.

4. Switchback the original Primary as a new primary.

Read Replica (RR) and DR Replica Handling

If your DB service includes Read Replica (RR) or DR Replica (DR) instances:

• Tessell upgrades replica instances first

• The source (Primary) instance is upgraded afterward

This sequencing helps reduce service impact.

Steps to Perform a Minor Version Patching

• Sign in to the Tessell Console.

• From the left navigation pane, go to DB Services and open the My Services App.

• Choose your MySQL DB service for which you want to perform patching.

• Take a pre-upgrade snapshot. Creating a snapshot ensures rollback capability in case of unexpected issues.

• Go to the Availability Machines tab.

• Navigate to Snapshots.

• Click Take Snapshot.

• If a newer patch is available for your database service, you will see Patch Available next to status. Hover over the Patch Available and Click Patch Now to see which new versions are available for your DB Service.

• It opens up Patch Database Engine Version window and in the menu:

  • Select the desired engine version from the dropdown.

  • Optionally, modify the number of instances to patch (default: all instances).

    Note: HA replicas cannot be excluded from patching.

  • Select the Patch Database Engine Version checkbox.

  • Click Start Patch.

• Once initiated, Tessell automatically performs:

  • Submits patch request

  • Installs new MySQL binaries

  • Performs rolling upgrade across instances

  • Updates DB service metadata

  • Brings service back to available state

No manual intervention is required during the process.

Rollback Considerations

• After a successful upgrade, you cannot revert the DB service to the previous engine version.

• If the upgrade fails, you can restore the pre-upgrade snapshot to create a new DB service running the previous version.

Major Version Upgrades

Major version upgrades may introduce changes that are not backward-compatible with existing applications.

Example:

• Upgrading from MySQL 5.7 to 8.0 version.

• Upgrading from MySQL 8.0 to 8.4 version.

Major upgrades may include:

• Removed or deprecated features

• Authentication changes

• Data dictionary changes

• SQL behavior differences

Because of potential incompatibilities, major version upgrades require careful planning and validation. They cannot be performed as an in-place upgrade through the Tessell Console.

You must validate and manually perform the upgrade in a staging environment before upgrading your production environment. The recommended high-level approach is as follows:

1. Review MySQL incompatibilities between current and target version by running MySQL upgrade pre-check (mysqlsh util checkForServerUpgrade) for your db service to identify potential issues.

2. In the Tessell console, provision a new MySQL service with the target major version.

3. Schedule a maintenance window for the cutover, as this process will require downtime.

4. Migrate your data from your current MySQL service to the MySQL service running with the target version by taking a full backup/logical dump and restore.

5. To reduce downtime, you can optionally set up Change Data Capture (CDC) or replication from the old service to the new service to keep them in sync until the cutover.

6. Update your application service pointing to the new MySQL service.

7. Validate application functionality.

8. Monitor performance and logs.