Database Reference
In-Depth Information
Table 9-6. Built-in job counters
Counter
Description
Launched map tasks
(
TOTAL_LAUNCHED_MAPS
)
The number of map tasks that were launched. Includes tasks that were
started speculatively (see
Speculative Execution
)
.
Launched reduce tasks
(
TOTAL_LAUNCHED_REDUCES
)
The number of reduce tasks that were launched. Includes tasks that
were started speculatively.
Launched uber tasks
(
TOTAL_LAUNCHED_UBERTASKS
)
The number of uber tasks (see
Anatomy of a MapReduce Job Run
)
that were launched.
Maps in uber tasks
(
NUM_UBER_SUBMAPS
)
The number of maps in uber tasks.
Reduces in uber tasks
(
NUM_UBER_SUBREDUCES
)
The number of reduces in uber tasks.
Failed map tasks
(
NUM_FAILED_MAPS
)
The number of map tasks that failed. See
Task Failure
for potential
causes.
Failed reduce tasks
(
NUM_FAILED_REDUCES
)
The number of reduce tasks that failed.
Failed uber tasks
(
NUM_FAILED_UBERTASKS
)
The number of uber tasks that failed.
Killed map tasks
(
NUM_KILLED_MAPS
)
The number of map tasks that were killed. See
Task Failure
for poten-
tial causes.
Killed reduce tasks
(
NUM_KILLED_REDUCES
)
The number of reduce tasks that were killed.
Data-local map tasks
(
DATA_LOCAL_MAPS
)
The number of map tasks that ran on the same node as their input data.
Rack-local map tasks
(
RACK_LOCAL_MAPS
)
The number of map tasks that ran on a node in the same rack as their
input data, but were not data-local.
Other local map tasks
(
OTHER_LOCAL_MAPS
)
The number of map tasks that ran on a node in a different rack to their
input data. Inter-rack bandwidth is scarce, and Hadoop tries to place
map tasks close to their input data, so this count should be low. See
Total time in map tasks
(
MILLIS_MAPS
)
The total time taken running map tasks, in milliseconds. Includes tasks
that were started speculatively. See also corresponding counters for
measuring core and memory usage (
VCORES_MILLIS_MAPS
and
MB_MILLIS_MAPS
).
Total time in reduce tasks
(
MILLIS_REDUCES
)
The total time taken running reduce tasks, in milliseconds. Includes
tasks that were started speculatively. See also corresponding counters
