Hadoop Questions Asked in Companies

Hadoop makes 5 splits as follows: One split for 64K files Two splits for 65MB files, and Two splits for 127MB files In Hadoop, the number of InputSplits is determined by the Hadoop framework based on the size of the input data and the configured block size. InputSplits are logical divisions of the input data … Read more

In Hadoop, SequenceFileInputFormat is used to read files in sequence. It is a specific compressed binary file format which passes data between the output of one MapReduce job to the input of some other MapReduce job. In Hadoop, SequenceFileInputFormat is a class that is used to read data stored in Hadoop’s SequenceFile format. The SequenceFile … Read more

In TextInputFormat, each line in the text file is a record. Value is the content of the line while Key is the byte offset of the line. For instance, Key: longWritable, Value: text In Hadoop, TextInputFormat is a class that is part of the Hadoop MapReduce framework. It is a specific input format used for … Read more

When a Hadoop job runs, it splits input files into chunks and assigns each split to a mapper for processing. It is called the InputSplit. In Hadoop, an InputSplit is a logical division of the input data that is fed into a MapReduce job. It represents a chunk of the input data that is processed … Read more

The ‘jps’ command is used for the retrieval of the status of daemons running the Hadoop cluster. To retrieve the status of daemons running in a Hadoop cluster, you can use the following command: bash hadoop-daemon.sh [–config confdir] [–script hdfs|yarn] [–hosts hostlistfile] command start|stop|status|etc. For example, to check the status of the NameNode daemon, you … Read more