Apache Spark Spark Core and RDDs 2

Question 1

Which method is used to persist an RDD in Spark?

Accepted Answer

cache() or persist()

Answer

cache() and persist() are used to persist an RDD; cache() is a shorthand for persist(StorageLevel.MEMORY_ONLY).

Question 2

What is a narrow transformation in Spark?

Accepted Answer

A transformation where each input partition contributes to only one output partition

Answer

Narrow transformations are those where each input partition maps to only one output partition, requiring no data shuffle.

Question 3

Which of the following is a wide transformation (shuffle) in Spark?

Accepted Answer

groupByKey()

Answer

groupByKey() is a wide transformation because it requires shuffling data across partitions to group all values for each key.

Question 4

What is lineage in Apache Spark?

Accepted Answer

The record of transformations used to build an RDD from base data

Answer

Lineage is the sequence of transformations that were applied to create an RDD, allowing Spark to recompute lost partitions.

Question 5

Which Spark RDD action returns the first n elements of the RDD?

Accepted Answer

take(n)

Answer

take(n) returns the first n elements of the RDD to the driver program.

Apache Spark Practice Test