This topic describes how to configure the parameters of an ApsaraDB RDS for MySQL instance in the ApsaraDB RDS console or by using the ApsaraDB RDS API. This topic also describes how to view the parameter configuration history in the ApsaraDB RDS console.
For more information about how to view the parameter settings of an RDS instance, see View the parameters of an ApsaraDB RDS for MySQL instance.
Precautions
- To ensure the stability of your RDS instance, you can configure only the parameters that are displayed in the ApsaraDB RDS console.
- When you configure the parameters of your RDS instance, you can view the value range of each parameter in the Value Range column on the Editable Parameters tab of the Parameters page in the ApsaraDB RDS console.
- The new values of some parameters take effect only after you restart your RDS instance. For more information, view the Force Restart column on the Editable Parameters tab of the Parameters page in the ApsaraDB RDS console. We recommend that you configure parameters during off-peak hours and make sure that your application is configured to automatically reconnect to your RDS instance.
Configure parameters
View the parameter configuration history
- Visit the RDS instance list, select a region above, and click the target instance ID.
- In the left-side navigation pane, click Parameters.
- On the page that appears, click the Edit History tab.
- Select a time range and click OK.
Configure parameters by using expressions
You can set a parameter to an expression for an RDS instance. If you set an instance type-related parameter to an expression, the value of the parameter dynamically changes when the instance type changes. This ensures the stability of the RDS instance.
In the example shown in the following figure, the innodb_buffer_pool_size parameter
is set to {DBInstanceClassMemory*3/4}
. If the value of the DBInstanceClassMemory variable changes, you do not need to change
the value of the innodb_buffer_pool_size parameter because the value of the innodb_buffer_pool_size
parameter dynamically changes.

The following table describes the supported expression syntax.
Category | Description | Example |
---|---|---|
Variables |
Note
|
{DBInstanceClassMemory*3/4} |
Operators |
|
|
Functions |
|
LEAST({DBInstanceClassMemory/256},10485760) |
FAQ
- After I configure the parameters of my RDS instance, do the new values of the parameters
immediately take effect? Do I need to restart my RDS instance?
After you configure the parameters of your RDS instance, the new values of some parameters take effect in approximately 5 minutes even if you do not restart your RDS instance. However, some parameters require you to restart your RDS instance to make the new values take effect. For more information, view the Force Restart column on the Editable Parameters tab of the Parameters page in the ApsaraDB RDS console.
- After I reconfigure the parameters of my RDS instance, why do the new values of the
parameters not take effect?
After you reconfigure the parameters of your RDS instance, you must click Apply Changes in the upper-right corner of the Editable Parameters tab on the Parameters page in the ApsaraDB RDS console to make the new values of the parameters take effect.
Related operations
Operation | Description |
---|---|
Modify parameters of an ApsaraDB for RDS instance | Reconfigures the parameters of an ApsaraDB RDS instance. |
Query the parameter template of an ApsaraDB for RDS instance | Queries the parameter templates that are available for an ApsaraDB RDS instance. |
Query parameter configurations | Queries the parameter settings of an ApsaraDB RDS instance. |