Configuring ClickHouse Parameters

This article describes how to modify the configuration of a
ClickHouse Cluster using the Instaclustr Console. It assumes that you have already provisioned a ClickHouse cluster in accordance with the steps in the article on Creating a ClickHouse Cluster. 

You can alternatively choose to update the cluster configuration via the Instaclustr Provisioning API or Terraform. Please note that using these methods you can only modify the values of a limited set of parameters. If you’re interested in modifying other parameters, please reach out to our support team.  

The available parameters are a mix of the global server settings and query-level settings.  

• The query-level parameters are applied to the “Default” user profile, and will not apply to users under different profiles, if you’ve created any.  

• Global server parameters instead will apply to all users. 

You can check the relevant documentation to determine the scope of a parameter. 

Modify 

You can “override” the available parameters with values of your choice to alter cluster behaviour to suit your requirements.  

1. To get started, after signing into the console, click on the dropdown button with the name of the ClickHouse cluster you want to modify.
2. To modify the configuration on the cluster, simply click on the Configuration button that appears in the drop down list. This will take you to a page which displays all configuration parameters available.
3. Once on the Configuration page, change the default value of an available configuration parameter to your desired value. The Status will change to “Override Pending”, indicating the setting has not been applied yet.
4. Once you’ve updated each parameter you’d like to update with the desired values then scroll to the bottom of the page and click “Apply Pending Changes”.
5. Applying the changes updates the ClickHouse configuration to the cluster and can take up to a couple of minutes. During this time, you are unable to apply further pending changes to the cluster.
6. The information box will confirm when the cluster has been updated. 
7. All overridden parameters now show the “Overridden” status and their respective new values. 

Resetting Parameter Values to Defaults 

1. The “Reset To Default” option is enabled allowing the parameter to be reset to the default value. 
2. Pressing “Reset To Default” sets the parameter status to “Reset Pending”, then the reset can be applied by selecting “Apply Pending Changes”.
3. The “Clear Pending Change” button restores the current value of a parameter, either “Default” or “Overridden”. Similarly the “Clear Pending Changes” button at the bottom of the page restores the current value of all parameters. 
4. The “Restore All” button will reset all parameters to the default value. This button requires confirmation via a pop up window and once “Proceed” is clicked the configuration will be loaded onto the cluster.