Upgrading a Minor Version

Scenarios

RDS for MySQL supports minor version upgrades to improve performance, add new functions, and fix bugs.

By default, a newly created DB instance uses the latest minor version. When a new minor version is released on Huawei Cloud, the Upgrade link is displayed in the DB Engine Version column on the Instances page. You can click Upgrade to go to the minor version upgrade page.

Figure 1 Version upgrade

Upgrade Methods

A minor version can be upgraded in either of the following ways:

• Upon submission: The system upgrades the minor version upon your manual submission of the upgrade request.
• In maintenance window: The system upgrades the minor version during the maintenance window you specified. For details about how to change the maintenance window, see Changing the Maintenance Window.

If the kernel version of your instance has potential risks or major defects, has expired, or has been brought offline, the system will notify you by SMS message or email and deliver an upgrade task during the maintenance window.

Precautions

• When any new minor version is released for addressing issues and vulnerabilities from the open source community, upgrade the minor version of your instance immediately or during the maintenance window.
• The upgrade will cause the DB instance to reboot and briefly interrupt services. To limit the impact of the upgrade, perform the upgrade during off-peak hours, or ensure that your applications support automatic reconnection.
• A minor version upgrade involves switchovers between primary and standby instances, which causes a brief service interruption. Besides, there can be two waits of up to 10s for a single SQL statement to update or write data because the default replication between primary and standby instances is semi-synchronous. To avoid the waits, change the replication mode to asynchronous before the upgrade.
• If primary and standby DB instances are deployed in the same AZ, a minor version upgrade will trigger a switchover. If they are deployed in different AZs, a minor version upgrade will trigger two switchovers.
• When you upgrade a minor version of a primary DB instance, minor versions of read replicas (if any) will also be upgraded automatically (they cannot be upgraded separately). Perform the upgrade during off-peak hours because the DB instance will be rebooted after the upgrade is complete.
• If your RDS instance is involved in a DRS task, upgrading the minor version may cause the DRS task to fail.
  You are advised to check the retention period of RDS instance binlogs before upgrading the minor version.

  • If the binlogs are within the retention period, the DRS task will automatically restart after the minor version is upgraded.
  • If the binlogs are beyond the retention period, you need to reconfigure or recreate a DRS task.
• A minor version upgrade cannot be rolled back after the upgrade is complete. If the upgrade fails, the DB instance will be automatically rolled back to the source version.
• You are advised to perform a full backup before upgrading a minor version.
• A minor version can be upgraded in minutes.
• DDL operations on events, such as CREATE EVENT, DROP EVENT, and ALTER EVENT, are not allowed during a minor version upgrade.

  During a minor version upgrade, if you are prompted that there are DDL operations being executed on the primary instance, do as follows:

  • Change the status of the event whose STATUS is SLAVESIDE_DISABLED to ENABLED or DISABLED, and then perform the upgrade.
  • Delete the events whose STATUS is SLAVESIDE_DISABLED and then perform the upgrade.

Constraints

• If the replication delay between primary and standby DB instances is longer than 300 seconds, the minor version cannot be upgraded.
• For primary/standby DB instances, the standby DB instance is upgraded first and then the primary DB instance is upgraded afterwards.
• Minor versions cannot be upgraded for DB instances with abnormal nodes.
• RDS for MySQL DB instances with the event scheduler function enabled do not support minor version upgrades. If you want to perform a minor version upgrade, disable event scheduler first. For operation details, see Enabling or Disabling Event Scheduler.
• TLSv1.1 is not supported for RDS for MySQL 8.0.28 or later versions. To modify the TLS version, change the value of the parameter loose_tls_version.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select a region.
3. Click in the upper left corner of the page and choose Databases > Relational Database Service.
4. On the Instances page, click the instance name to go to the Overview page.
5. Under DB Engine Version, click Upgrade Minor Version.
   Figure 2 Upgrading a minor version
   

6. In the displayed dialog box, select a scheduled time and click OK.
   • Upon submission: The system upgrades the minor version immediately after you have submitted your upgrade request.
   • In maintenance window: The system will upgrade the minor version during the maintenance window that you have configured.
   Figure 3 Selecting a scheduled time