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Documentation

5-minute quick start guide for Spark 3.0

In this tutorial, you'll learn how to setup a very simple Spark application for reading and writing data from/to Cassandra. Before you start, you need to have basic knowledge of Apache Cassandra and Apache Spark. Refer to Datastax and Cassandra documentation and Spark documentation.

Prerequisites

Install and launch a Cassandra cluster and a Spark cluster.

Configure a new Scala project with the Apache Spark and dependency.

The dependencies are easily retrieved via Maven Central

libraryDependencies += "com.datastax.spark" % "spark-cassandra-connector_2.12" % "3.5.1"

The spark-packages libraries can also be used with spark-submit and spark shell, these commands will place the connector and all of its dependencies on the path of the Spark Driver and all Spark Executors.

$SPARK_HOME/bin/spark-shell --packages com.datastax.spark:spark-cassandra-connector_2.12:3.5.1
$SPARK_HOME/bin/spark-submit --packages com.datastax.spark:spark-cassandra-connector_2.12:3.5.1

For the list of available versions, see:

This Connector does not depend on the Cassandra server code.

Building

See Building And Artifacts

Loading up the Spark-Shell

Run the spark-shell with the packages line for your version. This will include the connector and all of its dependencies on the Spark Class PathTo configure the default Spark Configuration pass key value pairs with --conf

$SPARK_HOME/bin/spark-shell --conf spark.cassandra.connection.host=127.0.0.1 \
                            --packages com.datastax.spark:spark-cassandra-connector_2.12:3.5.1
                            --conf spark.sql.extensions=com.datastax.spark.connector.CassandraSparkExtensions

This command would set the Spark Cassandra Connector parameter spark.cassandra.connection.host to 127.0.0.1. Change this to the address of one of the nodes in your Cassandra cluster.

The extensions configuration option enables Cassandra Specific Catalyst optimizations and functions.

Create a Catalog Reference to your Cassandra Cluster

spark.conf.set(s"spark.sql.catalog.mycatalog", "com.datastax.spark.connector.datasource.CassandraCatalog")

Create a keyspace and table in Cassandra

These lines will create an actual Keyspace and Table in Cassandra.

spark.sql("CREATE DATABASE IF NOT EXISTS mycatalog.testks WITH DBPROPERTIES (class='SimpleStrategy',replication_factor='1')")
spark.sql("CREATE TABLE mycatalog.testks.testtab (key Int, value STRING) USING cassandra PARTITIONED BY (key)")

//List their contents
spark.sql("SHOW NAMESPACES FROM mycatalog").show
spark.sql("SHOW TABLES FROM mycatalog.testks").show

Loading and analyzing data from Cassandra

Use the SparkSQL or a DataframeReader to Load a table

val df = spark.read.table("mycatalog.testks.testtab")
println(df.count)
df.show

//or

spark.sql("SELECT * FROM mycatalog.testks.testtab").show

Saving data from a dataframe to Cassandra

Add 10 more rows to the table:

spark
  .range(1, 10)
  .withColumnRenamed("id", "key")
  .withColumn("value", col("key").cast("string"))
  .writeTo("mycatalog.testks.testtab")
  .append

Accessing data with DataFrames More details on Connecting to Cassandra