MapReduce Types and Formats - Hadoop: The Definitive Guide - page 249

that have to be compatible with the MapReduce types are listed in the lower part of
Table 8-1 . Type conflicts are detected at runtime during job execution, and for this reason,
it is wise to run a test job using a small amount of data to flush out and fix any type in-
compatibilities.

Table 8-1. Configuration of MapReduce types in the new API

Property Job setter method Input

types

Intermediate
types

K1 V1 K2

Properties for configuring types:

• •

mapreduce.job.inputformat.class setInputFormatClass()

•

mapreduce.map.output.key.class setMapOutputKeyClass()

mapreduce.map.output.value.class setMapOutputValueClass()

mapreduce.job.output.key.class setOutputKeyClass()

mapreduce.job.output.value.class setOutputValueClass()

Properties that must be consistent with the types:

• • • mapreduce.job.map.class setMapperClass()

• mapreduce.job.combine.class setCombinerClass()

•

mapreduce.job.partitioner.class setPartitionerClass()

•

mapreduce.job.output.key.comparator.class setSortComparatorClass()

•

mapreduce.job.output.group.comparator.class setGroupingComparatorClass()

•

mapreduce.job.reduce.class setReducerClass()

mapreduce.job.outputformat.class setOutputFormatClass()