I would like to keep only a defined subset of a collection. I don\'t find any relevant information about it. It\'s hard to explain, so I put an exemple:
If I had a file with random integers on ea开发者_运维百科ch line and wanted to sort the file using Hadoop, what would my mapper and reducer\'s input/output key and value be?Yahoo has sorted Peta and T
I am using hadoop-0.20.2 from http://www.apache.org/dyn/closer.cgi/hadoop/common/ and I\'m using the following Eclipse plugin hadoop-0.20.1-eclipse-plugin.jar from http://code.google.com/p/hadoop-ecli
Given a huge data set of integers, what would be the advantages of using map and reduce techniques over traditional sorting algorithms such as q开发者_开发问答uicksort and mergesort?Map/reduce is more
Is it possible to run MongoDB commands like a query to grab additional data or to do an update from with in MongoDB\'s MapReduce command.Either in the Map or the Reduce function?
public static class Map extends MapReduceBase i开发者_开发技巧mplements Mapper MapReduceBase, Mapper and JobConf are deprecated in Hadoop 0.20.203.
I read Hadoop in Action and found that in Java using MultipleOutputFormat and MultipleOutputs classes we can reduce the data to multiple files but what I am not sure is how to achieve the same thing u
This is my first time using map/reduce. I want to write a program that processes a large log file. For example, if I was processing a log file that had records consisting of {Student, College, and GPA
In mongodb, I have a map function as below: var map = function() { emit( this.username, {count: 1, otherdata:otherdata} );
To create MapReduce jobs you can either use the old org.apache.hadoop.mapred package or the newer org.apache.hadoop.mapreduce package for Mappers and Reducers, Jobs ... The first one had been ma开发者
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