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Tableau Online

Tableau Online can connect to ClickHouse Cloud or on-premise ClickHouse setup via MySQL interface using the official MySQL data source.

ClickHouse Cloud setup​

Select Connect your app​

After creating your ClickHouse Cloud Service, on the Connect your app screen, select MySQL from the drop down.

Enable the MySQL interface​

Toggle the switch to enable the MySQL interface for this specific service. This will expose port 3306 for this service and prompt you with a MySQL connection screen that includes your unique MySQL username.

Alternatively, in order to enable the MySQL interface for an existing service:

Select Connect​

Ensure your service is in Running state then click on the service you want to enable the MySQL interface for. Select "Connect" from the left menu:

Choose MySQL​

Select MySQL from the Connect With drop down.

Enable the MySQL interface​

Toggle the switch to enable the MySQL interface for this specific service. This will expose port 3306 for this service and prompt you with your MySQL connection screen that include your unique MySQL username.

Creating a readonly MySQL user in ClickHouse Cloud​

ClickHouse Cloud automatically creates a mysql4<subdomain> user that shares the same password as the default user. The <subdomain> portion corresponds to the first part of your ClickHouse Cloud hostname.

This username format is required for compatibility with tools that establish secure connections but don't include SNI (Server Name Indication) data in their TLS handshake. Without SNI information, the system cannot perform proper internal routing, so the subdomain hint embedded in the username provides the necessary routing information. The MySQL console client is an example of a tool that requires this.

Tip

A recommended best practice is to create a new readonly MySQL user.

Note

For a ClickHouse Cloud hostname like foobar.us-east1.aws.clickhouse.cloud, the <subdomain> part equals to foobar, and a custom MySQL username could look like mysql4foobar_team1.

Create a readonly settings profile​

Create a settings profile to apply to your readonly user, setting the readonly setting to 1:

Create a new readonly MySQL user​

Create a user with a name following this format:

Apply the readonly_profile to the new user and make sure that the password is in double SHA1 format. For example:

Grant the new user permissions to access the desired tables​

Grant the new user the necessary permissions to interact with the desired tables or databases. For example, if you want to grant access to system.query_log only:

Note

For the readonly user, make sure to only grant SELECT permissions to the tables you want to access.

The newly created user can be used to connect to your ClickHouse Cloud service with the MySQL interface.

Troubleshooting multiple MySQL users in ClickHouse Cloud​

If you created a new MySQL user, and you see the following error while connecting via MySQL CLI client:

In this case, ensure that the username follows the mysql4<subdomain>_<username> format, as described (above).

On-premise ClickHouse server setup​

Please refer to the official documentation on how to set up a ClickHouse server with enabled MySQL interface.

Aside from adding an entry to the server's config.xml

it is also required to use Double SHA1 password encryption for the user that will be using MySQL interface.

Generating a random password encrypted with Double SHA1 from the shell:

The output should look like the following:

The first line is the generated password, and the second line is the hash we could use to configure ClickHouse.

Here is an example configuration for mysql_user that uses the generated hash:

/etc/clickhouse-server/users.d/mysql_user.xml

Replace password_double_sha1_hex entry with your own generated Double SHA1 hash.

Additionally, it is recommended to use use_mysql_types_in_show_columns to show the native MySQL types instead of ClickHouse ones in SHOW [FULL] COLUMNS query results, which allows BI tools to properly introspect the database schema when using MySQL connectors.

For example:

/etc/clickhouse-server/users.d/mysql_user.xml

or assign it to a different profile instead of the default one.

If you have the mysql binary available, you can test the connection from the commandline. Using the sample username (mysql_user) and password (LZOQYnqQN4L/T6L0) from above the command line would be:

Finally, configure the Clickhouse Server to listen on the desired IP address(es). For example, in config.xml, uncomment out the following to listen on all addresses:

Connecting Tableau Online to ClickHouse (on-premise without SSL)​

Login to your Tableau Cloud site and add a new Published Data Source.


Select "MySQL" from the list of available connectors.


Specify your connection details gathered during the ClickHouse setup.


Tableau Online will introspect the database and provide a list of available tables. Drag the desired table to the canvas on the right. Additionally, you can click "Update Now" to preview the data, as well as fine-tune the introspected field types or names.


After that, all that remains is to click "Publish As" in the top right corner, and you should be able to use a newly created dataset in Tableau Online as usual.

NB: if you want to use Tableau Online in combination with Tableau Desktop and share ClickHouse datasets between them, make sure you use Tableau Desktop with the default MySQL connector as well, following the setup guide that is displayed here if you select MySQL from the Data Source drop-down. If you have an M1 Mac, check this troubleshooting thread for a driver installation workaround.

Connecting Tableau Online to ClickHouse (cloud or on-premise setup with SSL)​

As it is not possible to provide the SSL certificates via the Tableau Online MySQL connection setup wizard, the only way is to use Tableau Desktop to set the connection up, and then export it to Tableau Online. This process is, however, pretty straightforward.

Run Tableau Desktop on a Windows or Mac machine, and select "Connect" -> "To a Server" -> "MySQL". Likely, it will be required to install the MySQL driver on your machine first. You can do that by following the setup guide that is displayed here if you select MySQL from the Data Source drop-down. If you have an M1 Mac, check this troubleshooting thread for a driver installation workaround.


Note

In the MySQL connection setup UI, make sure that the "SSL" option is enabled. ClickHouse Cloud's SSL certificate is signed by Let's Encrypt. You can download this root cert here.

Provide your ClickHouse Cloud instance MySQL user credentials and the path to the downloaded root certificate.


Choose the desired tables as usual (similarly to Tableau Online), and select "Server" -> "Publish Data Source" -> Tableau Cloud.


IMPORTANT: you need to select "Embedded password" in "Authentication" options.


Additionally, choose "Update workbook to use the published data source".


Finally, click "Publish", and your datasource with embedded credentials will be opened automatically in Tableau Online.

Known limitations (ClickHouse 23.11)​

All the known limitations has been fixed in ClickHouse 23.11. If you encounter any other incompatibilities, please do not hesitate to contact us or create a new issue.