Amazon Redshift Parameter Groups

In Amazon Redshift, you associate a parameter group with each cluster that you create. The parameter group is a group of parameters that apply to all of the databases that you create in the cluster. These parameters configure database settings such as query timeout and datestyle.

Each parameter group has several parameters to configure settings for the database. The list of available parameters depends on the parameter group family to which the parameter group belongs. The parameter group family is the version of the Amazon Redshift engine to which the parameters in the parameter group apply. The format of the parameter group family name is redshift-version where version is the engine version. For example, the current version of the engine is redshift-1.0.

Amazon Redshift provides one default parameter group for each parameter group family. The default parameter group has preset values for each of its parameters, and it cannot be modified. The format of the default parameter group name is default.parameter_group_family, where parameter_group_family is the version of the engine to which the parameter group belongs. For example, the default parameter group for the redshift-1.0 version is named default.redshift-1.0.

If you want to use different parameter values than the default parameter group, you must create a custom parameter group and then associate your cluster with it. Initially, the parameter values in a custom parameter group are the same as in the default parameter group. The initial source for all of the parameters is engine-default because the values are preset by Amazon Redshift. After you change a parameter value, the source changes to user to indicate that the value has been modified from its default value.

For parameter groups that you create, you can modify a parameter value at any time, or you can reset all parameter values to their defaults. You can also associate a different parameter group with a cluster. If you modify parameter values in a parameter group that is already associated with a cluster or you associate a different parameter group with the cluster, you might need to restart the cluster for the updated parameter values to take effect. If the cluster fails and is restarted by Amazon Redshift, your changes are applied at that time. For more information, see WLM Dynamic and Static Properties.

The following table shows the default parameter values at a glance with links to more in-depth information about each parameter. These are the default values for the redshift-1.0 parameter group family.

You can temporarily override a parameter by using the SET command in the database. The SET command overrides the parameter for the duration of your current session only. In addition to the parameters listed in the preceding table, you can also temporarily adjust the slot count by setting wlm_query_slot_count in the database. The wlm_query_slot_count parameter is not available for configuration in parameter groups. For more information about adjusting the slot count, see wlm_query_slot_count in the Amazon Redshift Database Developer Guide. For more information about temporarily overriding the other parameters, see Modifying the Server Configuration in the Amazon Redshift Database Developer Guide.

To configure Amazon Redshift parameters by using the AWS CLI, you use the modify-cluster-parameter-group command for a specific parameter group. You specify the parameter group to modify in parameter-group-name. You use the parameters parameter (for the modify-cluster-parameter-group command) to specify name/value pairs for each parameter that you want to modify in the parameter group.

After you modify parameter values, you must reboot any clusters that are associated with the modified parameter group. The cluster status displays applying for ParameterApplyStatus while the values are being applied, and then pending-reboot after the values have been applied. After you reboot, the databases in your cluster begin use the new parameter values. For more information about rebooting clusters, see Rebooting a Cluster.

Syntax

The following syntax shows how to use the modify-cluster-parameter-group command to configure a parameter. You replace both parameter_name and parameter_value with an actual parameter to modify and a value for that parameter. If you want to modify more than one parameter at the same time, separate each parameter and value set from the next with a space.

aws redshift modify-cluster-parameter-group --parameters ParameterName=parameter_name,ParameterValue=parameter_value

Example

The following example shows how to configure the statement_timeout and enable_user_activity_logging parameters for the myclusterparametergroup parameter group.

aws redshift modify-cluster-parameter-group 
--parameter-group-name myclusterparametergroup 
--parameters ParameterName=statement_timeout,ParameterValue=20000 ParameterName=enable_user_activity_logging,ParameterValue=true