Spark Cassandra Connector Error: java.lang.NoClassDefFoundError: com/datastax/spark/connector/TableRef

Question

Spark version:3.00
scala:2.12
Cassandra::3.11.4
spark-cassandra-connector_2.12-3.0.0-alpha2.jar

I am not using DSE. Below is my test code to write the dataframe into my Cassandra database.

        spark = SparkSession \
        .builder \
        .config("spark.jars","spark-streaming-kafka-0-10_2.12-3.0.0.jar,spark-sql-kafka-0-10_2.12-3.0.0.jar,kafka-clients-2.5.0.jar,commons-pool2-2.8.0.jar,spark-token-provider-kafka-0-10_2.12-3.0.0.jar,**spark-cassandra-connector_2.12-3.0.0-alpha2.jar**") \
        .config("spark.cassandra.connection.host", "127.0.0.1")\
        .config('spark.cassandra.output.consistency.level', 'ONE')\
        .appName("StructuredNetworkWordCount") \
        .getOrCreate()

    streamingInputDF = spark \
        .readStream \
        .format("kafka") \
        .option("kafka.bootstrap.servers", "192.168.56.1:9092") \
        .option("subscribe", "def") \
        .load()
##Dataset operations

    def write_to_cassandra(streaming_df,E):
    streaming_df\
        .write \
        .format("org.apache.spark.sql.cassandra") \
        .options(table="a", keyspace="abc") \
         .save()
       
    q1 =sites_flat.writeStream \
    .outputMode('update') \
    .foreachBatch(write_to_cassandra) \
    .start()
q1.awaitTermination()

I am able to do some operations to dataframe and print it to the console but I am not able to save or even read it from my Cassandra database. The error i am getting is:

      File "C:\opt\spark-3.0.0-bin-hadoop2.7\python\lib\py4j-0.10.9-src.zip\py4j\protocol.py", line 328, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o70.load.
: java.lang.NoClassDefFoundError: com/datastax/spark/connector/TableRef
    at org.apache.spark.sql.cassandra.DefaultSource$.TableRefAndOptions(DefaultSource.scala:142)
    at org.apache.spark.sql.cassandra.DefaultSource.createRelation(DefaultSource.scala:56)
    at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:339)
    at org.apache.spark.sql.DataFrameReader.loadV1Source(DataFrameReader.scala:279)
    at org.apache.spark.sql.DataFrameReader.$anonfun$load$2(DataFrameReader.scala:268)
    at scala.Option.getOrElse(Option.scala:189)
    at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:268)
    at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:203)

I have tried with other cassandra connector version(2.5) but getting the same error Please help!!!

Alex_Ott_18627 · Answer

The problem is that you're using spark.jars options that includes only provided jars into the classpath. But the TableRef case class is in the spark-cassandra-connector-driver package that is dependency for spark-cassandra-connector. To fix this problem, it's better to start the pyspark or spark-submit with --packages com.datastax.spark:spark-cassandra-connector_2.12:3.0.0-alpha2 (same for kafka support) - in this case Spark will fetch all necessary dependencies & put them into classpath.

P.S. With alpha2 release you may get problems with fetching some dependencies, like, ffi, groovy, etc. - this is a known bug (mostly in Spark): SPARKC-599, that is already fixed, and we'll hopefully get beta drop very soon.

Update (14.03.2021): It's better to use assembly version of SCC that includes all necessary dependencies.

P.P.S. for writing to Cassandra from Spark Structured Streaming, don't use foreachbatch, just use as normal data sink:

     val query = streamingCountsDF.writeStream
      .outputMode(OutputMode.Update)
      .format("org.apache.spark.sql.cassandra")
      .option("checkpointLocation", "webhdfs://192.168.0.10:5598/checkpoint")
      .option("keyspace", "test")
      .option("table", "sttest_tweets")
      .start()

user_7059424 · Answer

I ran into the same problem,try it :



    org.apache.spark
    spark-core_2.12
    2.4.3

version compatibility is presumed to be the cause

Spark Cassandra Connector Error: java.lang.NoClassDefFoundError: com/datastax/spark/connector/TableRef

2 Answers