in Hadoop by
How is identity mapper different from chain mapper?

1 Answer

0 votes

Identity Mapper

Chain Mapper

This is the default mapper that is chosen when no mapper is specified in the MapReduce driver class.

It implements identity function, which directly writes all its key-value pairs into output.

It is defined in old MapReduce API (MR1) in: org.apache.Hadoop.mapred.lib.package

This class is used to run multiple mappers in a single map task.

The output of the first mapper becomes the input to the second mapper, second to third and so on.

It is defined in: org.apache.Hadoop.mapreduce.lib.chain.ChainMapperpackage

Click here to read more about Loan/Mortgage
Click here to read more about Insurance

Related questions

0 votes
asked Jun 7, 2020 in Hadoop by Robindeniel
0 votes
asked Dec 3, 2020 in Hive by sharadyadav1986
0 votes
asked Nov 16, 2020 in BlockChain by rajeshsharma
0 votes
asked Sep 19, 2020 in XML by SakshiSharma
0 votes
asked May 21, 2020 in Git by SakshiSharma