frameworks - Simple explanation of MapReduce? - Stack Overflow
Aug 26, 2008 · MapReduce is a method to process vast sums of data in parallel without requiring the developer to write any code other than the mapper and reduce functions. The map function takes …
mapreduce - Does Spark internally use Map-Reduce? - Stack Overflow
Feb 3, 2019 · Compared to MapReduce, which creates a DAG with two predefined stages - Map and Reduce, DAGs created by Spark can contain any number of stages. DAG is a strict generalization of …
How does the MapReduce sort algorithm work? - Stack Overflow
MapReduce's use of input files and lack of schema support prevents the performance improvements enabled by common database system features such as B-trees and hash partitioning, though …
What is the purpose of shuffling and sorting phase in the reducer in ...
Mar 3, 2014 · Then, the MapReduce job stops at the map phase, and the map phase does not include any kind of sorting (so even the map phase is faster). Tom White has been an Apache Hadoop …
Setting the number of map tasks and reduce tasks - Stack Overflow
Jul 31, 2011 · For each input split a map task is spawned. So, over the lifetime of a mapreduce job the number of map tasks is equal to the number of input splits. mapred.map.tasks is just a hint to the …
what are the disadvantages of mapreduce? - Stack Overflow
Sep 3, 2013 · What are the disadvantages of mapreduce? There are lots of advantages of mapreduce. But I would like to know the disadvantages of mapreduce too.
Good MapReduce examples - Stack Overflow
Sep 12, 2012 · MapReduce is a framework originally developed at Google that allows for easy large scale distributed computing across a number of domains. Apache Hadoop is an open source …
mapreduce - When do reduce tasks start in Hadoop? - Stack Overflow
Jul 26, 2012 · In Hadoop when do reduce tasks start? Do they start after a certain percentage (threshold) of mappers complete? If so, is this threshold fixed? What kind of threshold is typically used?
A starting point for learning how to implement MapReduce/Hadoop in ...
Also note that for testing/learning things you can run Hadoop on your local machine without having an actual cluster. UPDATE: As for understanding Map Reduce (that is how to identify and express …
Can you explain when and why mapreduce is invoked in hive
Jun 18, 2015 · Can you explain when and why mapreduce is invoked in hive Asked 10 years, 7 months ago Modified 7 years, 8 months ago Viewed 16k times