what does "vcore-seconds" in hadoop job log mean?

Question

Job Counters
    Launched map tasks=3
    Launched reduce tasks=45
    Data-local map tasks=1
    Rack-local map tasks=2
    Total time spent by all maps in occupied slots (ms)=29338
    Total time spent by all reduces in occupied slots (ms)=200225
    Total time spent by all map tasks (ms)=29338
    Total time spent by all reduce tasks (ms)=200225
    Total vcore-seconds taken by all map tasks=29338
    Total vcore-seconds taken by all reduce tasks=200225
    Total megabyte-seconds taken by all map tasks=30042112
    Total megabyte-seconds taken by all reduce tasks=205030400

what does "vcore-seconds" mean and what is the difference between "vcore-seconds " and "Total time spent"

Answer 1

There isn't a official documentation about this metrics, but if I understand fine (see here), vcore-seconds is the sum of seconds in which Hadoop allocate vcore for some task.

I think this metric show how much time spend your MapReduce application in Map and Reduce phases, without involved other tasks (Scheduled task, shuffle and sort intermediate keys, etc...)