spark notes
  • Introduction
  • Databricks
  • Concepts
  • Spark Execution Flow
    • SparkContext and SparkSession
  • Resilient Distributed Dataset (RDD)
    • Caching
    • Pair RDDs
    • Transformations
      • Depedency Resolution
    • Actions
    • Persistence
    • RDD lineage
    • Types of RDDs
    • Loading Data into RDDs
    • Data Locality with RDDs
    • How Many Partitions Does An RDD Have
  • Spark job submission breakdown
  • Why Cluster Manager
  • SparkContext and its components
  • Spark Architecture
    • Stages
    • Tasks
    • Executors
    • RDD
    • DAG
    • Jobs
    • Partitions
  • Spark Deployment Modes
  • Running Modes
  • Spark Execution Flow
  • DataFrames, Datasets,RDDs
  • SparkSQL
    • Architecture
    • Spark Session
  • Where Does Map Reduce Does not Fit
  • Actions
    • reduceByKey
    • count
    • collect, take, top, and first Actions
    • take
    • top
    • first
    • The reduce and fold Actions
  • DataSets
  • Spark Application Garbage Collector
  • How Mapreduce works in spark
  • Notes
  • Scala
  • Spark 2.0
  • Types Of RDDs
    • MapPartitionsRDD
  • Spark UI
  • Optimization
    • Tungsten
  • Spark Streaming
    • Notes
    • Flow
  • FlatMap - Different Variations
  • Examples
  • Testing Spark
  • Passing functions to Spark
  • CONFIGURATION, MONITORING, AND TUNING
  • References
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  1. Actions

count

PreviousreduceByKeyNextcollect, take, top, and first Actions

Last updated 5 years ago

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The count action returns the number of elements or records in an RDD. It can be called at any time against any Spark RDD, causing the RDD and all of the RDDs in its lineage to be evaluated. For this reason, count is often a convenient way to force evaluation of an RDD.

Syntax:

RDD.count()