Process & Analyze PostgreSQL Data in Databricks (AWS)

Databricks is a cloud-based service that provides data processing capabilities through Apache Spark. When paired with the CData JDBC Driver, customers can use Databricks to perform data engineering and data science on live PostgreSQL data. This article explains how to host the CData JDBC Driver in AWS, as well as connect to and process live PostgreSQL data in Databricks.

With built-in optimized data processing, the CData JDBC Driver offers unmatched performance for interacting with live PostgreSQL data. When you issue complex SQL queries to PostgreSQL, the driver pushes supported SQL operations, like filters and aggregations, directly to PostgreSQL and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations). Its built-in dynamic metadata querying allows you to work with and analyze PostgreSQL data using native data types.

Install the CData JDBC Driver in Databricks

To work with live PostgreSQL data in Databricks, install the driver on your Databricks cluster.

1. Navigate to your Databricks administration screen and select the target cluster.
2. On the Libraries tab, click "Install New."
3. Select "Upload" as the Library Source and "Jar" as the Library Type.
4. Upload the JDBC JAR file (cdata.jdbc.postgresql.jar) from the installation location (typically C:\Program Files\CData[product_name]\lib).

👁 Loading the JDBC JAR File into AWS

Access PostgreSQL Data in your Notebook: Python

With the JAR file installed, we are ready to work with live PostgreSQL data in Databricks. Start by creating a new notebook in your workspace. Name the notebook, select Python as the language (though Scala is available as well), and choose the cluster where you installed the JDBC driver. When the notebook launches, we can configure the connection, query PostgreSQL, and create a basic report.

Configure the Connection to PostgreSQL

Connect to PostgreSQL by referencing the JDBC Driver class and constructing a connection string to use in the JDBC URL. Additionally, you will need to set the property in the JDBC URL (unless you are using a Beta driver). You can view the licensing file included in the installation for information on how to set this property.

Step 1: Connection Information

driver = "cdata.jdbc.postgresql.PostgreSQLDriver"
url = "jdbc:postgresql:RTK=5246...;User=postgres;Password=admin;Database=postgres;Server=127.0.0.1;Port=5432;"

Built-in Connection String Designer

For assistance in constructing the JDBC URL, use the connection string designer built into the PostgreSQL JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.postgresql.jar

Fill in the connection properties and copy the connection string to the clipboard.

To connect to PostgreSQL, set the Server, Port (the default port is 5432), and Database connection properties and set the User and Password you wish to use to authenticate to the server. If the Database property is not specified, the data provider connects to the user's default database.

SSH Connectivity for PostgreSQL

You can use SSH (Secure Shell) to authenticate with PostgreSQL, whether the instance is hosted on-premises or in supported cloud environments. SSH authentication ensures that access is encrypted (as compared to direct network connections).

SSH Connections to PostgreSQL in Password Auth Mode

To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

• User: PostgreSQL User name
• Password: PostgreSQL Password
• Database: PostgreSQL database name
• Server: PostgreSQL Server name
• Port: PostgreSQL port number like 3306
• UserSSH: "true"
• SSHAuthMode: "Password"
• SSHPort: SSH Port number
• SSHServer: SSH Server name
• SSHUser: SSH User name
• SSHPassword: SSH Password

SSH Connections to PostgreSQL in Public Key Auth Mode

To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

• User: PostgreSQL User name
• Password: PostgreSQL Password
• Database: PostgreSQL database name
• Server: PostgreSQL Server name
• Port: PostgreSQL port number like 3306
• UserSSH: "true"
• SSHAuthMode: "Public_Key"
• SSHPort: SSH Port number
• SSHServer: SSH Server name
• SSHUser: SSH User name
• SSHClientCret: the path for the public key certificate file

👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)

Load PostgreSQL Data

Once you configure the connection, you can load PostgreSQL data as a dataframe using the CData JDBC Driver and the connection information.

Step 2: Reading the data

remote_table = spark.read.format ( "jdbc" ) \
	.option ( "driver" , driver) \
	.option ( "url" , url) \
	.option ( "dbtable" , "Orders") \
	.load ()

Display PostgreSQL Data

Check the loaded PostgreSQL data by calling the display function.

Step 3: Checking the result

display (remote_table.select ("ShipName"))

👁 Displaying PostgreSQL Data

Analyze PostgreSQL Data in Databricks

If you want to process data with Databricks SparkSQL, register the loaded data as a Temp View.

Step 4: Create a view or table

remote_table.createOrReplaceTempView ( "SAMPLE_VIEW" )

With the Temp View created, you can use SparkSQL to retrieve the PostgreSQL data for reporting, visualization, and analysis.

% sql

SELECT ShipName, ShipCity FROM SAMPLE_VIEW ORDER BY ShipCity DESC LIMIT 5

👁 Displaying PostgreSQL Data

The data from PostgreSQL is only available in the target notebook. If you want to use it with other users, save it as a table.

remote_table.write.format ( "parquet" ) .saveAsTable ( "SAMPLE_TABLE" )

Download a free, 30-day trial of the CData JDBC Driver for PostgreSQL and start working with your live PostgreSQL data in Databricks. Reach out to our Support Team if you have any questions.