Why aren't the updated parameter values taking effect after I change the parameter values in an Amazon RDS parameter group?

Resolution

This happens because the parameter that you updated in the parameter group for your Amazon RDS DB instance is a static parameter. DB instance parameters are either static or dynamic. When you update the value of a static parameter and save the updates to the DB parameter group, the parameter changes don't take effect immediately. You must manually reboot the associated DB instance for the parameter group changes to take effect.

When you update a dynamic parameter, the parameter changes are applied to your DB instance immediately. In this case, you don't have to reboot the DB instance.

To check if the parameter that you're trying to modify is static or dynamic, do the following:

1. Open the Amazon RDS console.
2. In the navigation pane, choose Parameter groups.
3. In the list of parameter groups displayed, choose the parameter group that you need to modify.
4. For the parameter that you need to modify, check the column Apply type.
   This column displays whether the parameter is dynamic or static.

You can also run the following AWS Command Line Interface (AWS CLI) command to verify whether a parameter is static or dynamic. This command returns the list of parameters in a parameter group along with Apply type:

aws rds describe-db-parameters --db-parameter-group-name test_parameter_group --query "Parameters[*].[ParameterName,ApplyType]"

Be sure to replace test_parameter_group with the name of your custom parameter group.

Note: If you receive errors when running AWS CLI commands, make sure that you’re using the most recent version of the AWS CLI.

If the parameter that you modified is static, the RDS console shows the DB parameter group with a status of pending-reboot. To check the status of the parameter group, do the following:

1. Open the Amazon RDS console.
2. In the navigation pane, choose Databases, and then choose the DB instance.
3. Choose the Configuration tab.
   You can view the parameter group associated with the instance and status of the parameter group in this tab.

You can also run the following AWS CLI command to verify the status of a parameter group:

aws rds describe-db-instances --db-instance-identifier instance_identifier --query "DBInstances[*]".[DBInstanceIdentifier,DBParameterGroups]

Be sure to replace instance_identifier with the name of your RDS instance.

If the parameter that you're modifying is static, then reboot the instance for the parameter changes to take effect. For more information, see Rebooting a DB instance.

Rebooting a DB instance results in a momentary outage. During this outage, the DB instance status is set to rebooting status. After the instance is rebooted successfully, the changes to the static parameters take effect on the associated RDS instance. The status of the parameter group changes from pending-reboot to in-sync.

Note: When you associate a new DB parameter group with a DB instance, the RDS console shows the DB parameter group with a status of pending-reboot. You must reboot the instance for the modified static and dynamic parameters to be applied. However, if you modify dynamic parameters in the newly associated DB parameter group, these changes are applied immediately without a reboot.

Related information

How do I modify the values of an Amazon RDS DB parameter group?

Working with parameter groups