Why we cannot do aggregation (addition) in a mapper? Why we require reducer for that?
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What is the functionality of jobtracker in hadoop? How many instances of a jobtracker run on hadoop cluster?
What infrastructure do we need to process 100 TB data using Hadoop?
Can the balancer be run while Hadoop is in use?
Is a job split into maps?
Who invented hadoop?
Explain Erasure Coding in Apache Hadoop?
What is the heartbeat used for?
How does an hadoop application look like or their basic components?
Which are the two types of 'writes' in HDFS?
What is a spill factor with respect to the ram?
What mechanism does hadoop framework provides to synchronize changes made in distribution cache during runtime of the application?
How will you make changes to the default configuration files?
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