Vanrasoft Technologies interview questions

What is the difference between RDD, DataFrame, and Dataset in Spark? What is lazy evaluation in Apache Spark? What are transformations and actions in Spark? What is the role of the Catalyst Optimizer in Spark SQL? How does Spark achieve fault tolerance? What is a DAG in Spark? How does Spark handle data partitioning? What is the difference between narrow and wide transformations? What is a broadcast variable and when should you use it? Explain the use of accumulators in Spark.