![]() ![]() ![]() Finally, RDDs automatically recover from node failures.Ī second abstraction in Spark is shared variables that can be used in parallel operations. ![]() Users may also ask Spark to persist an RDD in memory, allowing it to be reused efficiently across parallel operations. RDDs are created by starting with a file in the Hadoop file system (or any other Hadoop-supported file system), or an existing Scala collection in the driver program, and transforming it. The main abstraction Spark provides is a resilient distributed dataset (RDD), which is a collection of elements partitioned across the nodes of the cluster that can be operated on in parallel. At a high level, every Spark application consists of a driver program that runs the user’s main function and executes various parallel operations on a cluster. ![]()
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