Modifying Parameters of an RDS for MySQL Instance

You can change parameter values in a custom parameter template and apply it to optimize RDS database performance.

You can only change the values in custom parameter templates. You cannot change the values in default parameter templates.

Global parameters can only be modified on the console. Session-level parameters can be modified using SQL statements. When you modify a parameter, the time when modifications take effect varies with the parameter type.

The RDS console displays the statuses of DB instances that the parameter template applies to. For example, if the DB instance has not yet used the latest modifications made to its parameter template, its status is Parameter change. Pending reboot. You need to manually reboot the DB instance for the latest modifications to take effect for that DB instance.

RDS has default parameter templates whose parameter values cannot be changed. You can view these parameter values by clicking the default parameter templates. If a custom parameter template with incorrect settings is applied to a DB instance, this instance may fail to start. If this happens, you can re-configure the custom parameter template based on the settings of the default parameter template.

Modifying a Custom Parameter Template and Applying It to a DB Instance

Log in to the management console.
Click in the upper left corner of the page and choose Databases > Relational Database Service.
Choose Parameter Templates in the navigation pane on the left. On the Custom Templates page, click the target parameter template.
On the Parameters page, modify parameters as required.

For parameter details, see Suggestions on RDS for MySQL Parameter Tuning.

Available operations are as follows:
- To save the modifications, click Save.
- To cancel the modifications, click Cancel.
- To preview the modifications, click Preview.
Click Change History to view the changes.
Apply the parameter template to your DB instance. For details, see Applying a Parameter Template.
View the status of the DB instance to which the parameter template has been applied.

If the DB instance status is Parameter change. Pending reboot, you need to reboot the DB instance for the modifications to take effect.
- The DB instance reboot caused by instance class changes will not make parameter modifications take effect.
- If you have modified parameters of a primary DB instance, you need to reboot the primary DB instance for the modifications to take effect. (For primary/standby DB instances, the parameter modifications are also applied to the standby DB instance.)
- If you have modified parameters of a read replica, you need to reboot the read replica for the modifications to take effect.

Modifying Parameters of a DB Instance

Log in to the management console.
Click in the upper left corner of the page and choose Databases > Relational Database Service.
On the Instances page, click the target DB instance.
In the navigation pane on the left, choose Parameters. On the displayed page, modify parameters as required.
Check the value in the Effective upon Reboot column.
- If the value is Yes and the DB instance status on the Instances page is Parameter change. Pending reboot, a reboot is required for the modifications to take effect.
  
  If you have modified parameters of a primary DB instance, you need to reboot the primary DB instance for the modifications to take effect. (For primary/standby DB instances, the parameter modifications are also applied to the standby DB instance.)
  
  If you have modified parameters of a read replica, you need to reboot the read replica for the modifications to take effect.
- If the value is No, the modifications take effect immediately.
- To save the modifications, click Save.
- To cancel the modifications, click Cancel.
- To preview the modifications, click Preview.
After parameters are modified, you can click Change History to view parameter modification details.