MySQL のFederated Table としてDatabricks データを連携利用する

SQL Gateway を使って、MySQL リモーティングサービスを作成し、Databricks のMySQL Federated Table を構築できます。CData ODBC Driver for Databricks のMySQL インターフェースのdeamon になります。サービス起動後、MySQL のFEDERATED ストレージエンジンを使ってサーバーおよびテーブルを作成します。Databricks data をMySQL テーブルのように使いましょう。

Databricks データへの接続

If you have not already done so, provide values for the required connection properties in the data source name (DSN). You can use the built-in Microsoft ODBC Data Source Administrator to configure the DSN. This is also the last step of the driver installation. See the "Getting Started" chapter in the help documentation for a guide to using the Microsoft ODBC Data Source Administrator to create and configure a DSN.

To connect to a Databricks cluster, set the properties as described below.

Note: The needed values can be found in your Databricks instance by navigating to Clusters, and selecting the desired cluster, and selecting the JDBC/ODBC tab under Advanced Options.

• Server: Set to the Server Hostname of your Databricks cluster.
• HTTPPath: Set to the HTTP Path of your Databricks cluster.
• Token: Set to your personal access token (this value can be obtained by navigating to the User Settings page of your Databricks instance and selecting the Access Tokens tab).

SQL Gateway の設定

See the SQL Gateway Overview to set up connectivity to Databricks data as a virtual MySQL database. You will configure a MySQL remoting service that listens for MySQL requests from clients. The service can be configured in the SQL Gateway UI.

Databricks Data のFEDERATED サーバーおよびテーブルを作成

After you have configured and started the service, create a FEDERATED server to simplify the process of creating FEDERATED tables:

FEDERATED サーバーの作成

The following statement will create a FEDERATED server based on the ODBC Driver for Databricks. Note that the username and password of the FEDERATED server must match a user account you defined on the Users tab of the SQL Gateway.

CREATE SERVER fedDatabricks
FOREIGN DATA WRAPPER mysql
OPTIONS (USER 'sql_gateway_user', PASSWORD 'sql_gateway_passwd', HOST 'sql_gateway_host', PORT ####, DATABASE 'CData Databricks Sys');

FEDERATED テーブルの作成

To create a FEDERATED table using our newly created server, use the CONNECTION keyword and pass the name of the FEDERATED server and the remote table (Customers). Refer to the following template for the statement to create a FEDERATED table:

CREATE TABLE fed_customers (
  ...,
  city  TYPE(LEN),
  companyname  TYPE(LEN),
  ...,
)
ENGINE=FEDERATED
DEFAULT CHARSET=latin1
CONNECTION='fedDatabricks/customers';

NOTE: The table schema for the FEDERATED table must match the remote table schema exactly. You can always connect directly to the MySQL remoting service using any MySQL client and run a SHOW CREATE TABLE query to get the table schema.

クエリの実行

You can now execute queries to the Databricks FEDERATED tables from any tool that can connect to MySQL, which is particularly useful if you need to JOIN data from a local table with data from Databricks. Refer to the following example:

SELECT 
  fed_customers.city, 
  local_table.custom_field 
FROM 
  local_table 
JOIN 
  fed_customers 
ON 
  local_table.foreign_city = fed_customers.city;