groupByKey vs reduceByKey vs aggregateByKey in Apache Spark/Scala
harshitjain.home.blog › 2019/09/08 › groupbykey-vsSep 8, 2019 · groupByKey vs reduceByKey vs aggregateByKey in Apache Spark/Scala. September 8, 2019 by HARHSIT JAIN, posted in Scala, Spark. The primary goal when choosing an arrangement of operators is to reduce the number of shuffles and the amount of data shuffled. This is because shuffles are fairly expensive operations; all shuffle data must be written to disk and then transferred over the network. repartition , join , cogroup, and any of the *By or *ByKey transformations can result in shuffles.
scala - groupBykey in spark - Stack Overflow
stackoverflow.com › questions › 31978226Aug 13, 2015 · 1) groupByKey (2) does not return first 2 results, the parameter 2 is used as number of partitions for the resulting RDD. See docs. 2) collect does not take Int parameter. See docs. 3) split takes 2 types of parameters, Char or String. String version uses Regex so "|" needs escaping if intended as literal. Share Improve this answer Follow