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Get the Report →How to connect and process Cassandra Data from Azure Databricks
Use CData, Azure, and Databricks to perform data engineering and data science on live Cassandra Data
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 Cassandra data. This article walks through hosting the CData JDBC Driver in Azure, as well as connecting to and processing live Cassandra data in Databricks.
With built-in optimized data processing, the CData JDBC driver offers unmatched performance for interacting with live Cassandra data. When you issue complex SQL queries to Cassandra, the driver pushes supported SQL operations, like filters and aggregations, directly to Cassandra 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 Cassandra data using native data types.
Install the CData JDBC Driver in Azure
To work with live Cassandra data in Databricks, install the driver on your Azure cluster.
- Navigate to your Databricks administration screen and select the target cluster.
- On the Libraries tab, click "Install New."
- Select "DBFS" as the Library Source and "Jar" as the Library Type.
- Upload the JDBC JAR file (cdata.jdbc.cassandra.jar) from the installation location (typically C:\Program Files\CData[product_name]\lib).
Connect to Cassandra from Databricks
With the JAR file installed, we are ready to work with live Cassandra data in Databricks. Start by creating a new notebook in your workspace. Name the workbook, make sure Python is selected as the language (which should be by default), click on Connect and under General Compute select the cluster where you installed the JDBC driver (should be selected by default).
Configure the Connection to Cassandra
Connect to Cassandra by referencing the class for the JDBC Driver and constructing a connection string to use in the JDBC URL. Additionally, you will need to set the RTK 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.
driver = "cdata.jdbc.cassandra.CassandraDriver" url = "jdbc:cassandra:RTK=5246...;Database=MyCassandraDB;Port=7000;Server=127.0.0.1;"
Built-in Connection String Designer
For assistance in constructing the JDBC URL, use the connection string designer built into the Cassandra JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.
java -jar cdata.jdbc.cassandra.jar
Fill in the connection properties and copy the connection string to the clipboard.
Set the Server, Port, and Database connection properties to connect to Cassandra. Additionally, to use internal authentication set the User and Password connection properties.
Load Cassandra Data
Once the connection is configured, you can load Cassandra data as a dataframe using the CData JDBC Driver and the connection information.
remote_table = spark.read.format ( "jdbc" ) \ .option ( "driver" , driver) \ .option ( "url" , url) \ .option ( "dbtable" , "Customer") \ .load ()
Display Cassandra Data
Check the loaded Cassandra data by calling the display function.
display (remote_table.select ("City"))
Analyze Cassandra Data in Azure Databricks
If you want to process data with Databricks SparkSQL, register the loaded data as a Temp View.
remote_table.createOrReplaceTempView ( "SAMPLE_VIEW" )
The SparkSQL below retrieves the Cassandra data for analysis.
result = spark.sql("SELECT City, SUM(TotalDue) FROM SAMPLE_VIEW GROUP BY City")
The data from Cassandra 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 Apache Cassandra and start working with your live Cassandra data in Azure Databricks. Reach out to our Support Team if you have any questions.