After one run of a 10 map, 3 reduce sort job, the mapred metrics report:
After the second (w/ one manually killed reduce)
The counters report the expected 10/3 map/reduce completions, the second job reporting a single failure.
- The maps_launched and reduces_launched counts are likely recording setup and cleanup tasks as well
- After being recorded among launched tasks, it looks like setup and cleanup are not included among completed tasks
- tasks_completed on the TaskTracker should include only user tasks
- The reduces_launched count makes little sense to me. With three reduces launched per job and one failed, what's the other launched reduce counting?