Hadoop Interview questions

Total available count: 27
Subject - Apache
Subsubject - Hadoop

What is Speculative Execution of a tasks?

Speculative tasks or task strugglers are tasks that run slower than most of the all tasks in a job. Speculative execution of tasks is a health-check procedure that checks for tasks to be speculated, i.e. running slower in a stage than the median of all successfully completed tasks in a task set. Such slow tasks will be re-launched in another worker. It will not stop the slow tasks, but run a new copy in parallel.

Next 5 interview question(s)

What is Task, with regards to Spark Job execution?
What is DAGSchedular and how it performs?
Please define executors in detail?
Please explain, how workers work, when a new Job submitted to them?
What are the workers?