hadoop - Lifespan of mapper class instance -


a mapper class instance created , used 1 inputsplit (or mapper task)? or multiple mapper class instances can handling 1 inputsplit (or mapper task)?

each input split handed mapper, , mapper process single input split.

however if have mapper speculative execution turned on, input split can run 2 mappers on different nodes in parallel (there conditions trigger speculative execution, should able google them).

also, if map task fails, input split scheduled run on cluster node map task.


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