$ hadoop jar hadoop-mapreduce-examples-3.0.0-SNAPSHOT.jar wordcount -Dmapreduce.job.reduces=10 wikimedia out1
(snip)
16/04/26 12:43:26 INFO mapreduce.Job: Counters: 50
File System Counters
FILE: Number of bytes read=32688875608
FILE: Number of bytes written=46793855889
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=2637796949
HDFS: Number of bytes written=10112132366
HDFS: Number of read operations=122
HDFS: Number of large read operations=0
HDFS: Number of write operations=20
Job Counters
Killed map tasks=1
Launched map tasks=24
Launched reduce tasks=10
Data-local map tasks=24
Total time spent by all maps in occupied slots (ms)=4377577
Total time spent by all reduces in occupied slots (ms)=2886069
Total time spent by all map tasks (ms)=4377577
Total time spent by all reduce tasks (ms)=962023
Total vcore-milliseconds taken by all map tasks=4377577
Total vcore-milliseconds taken by all reduce tasks=962023
Total megabyte-milliseconds taken by all map tasks=4482638848
Total megabyte-milliseconds taken by all reduce tasks=2955334656
Map-Reduce Framework
Map input records=185213309
Map output records=740850316
Map output bytes=18236248777
Map output materialized bytes=14106607147
Input split bytes=3240
Combine input records=955976839
Combine output records=393399713
Reduce input groups=84421738
Reduce shuffle bytes=14106607147
Reduce input records=178273190
Reduce output records=84421738
Spilled Records=691310164
Shuffled Maps =240
Failed Shuffles=0
Merged Map outputs=240
GC time elapsed (ms)=30978
CPU time spent (ms)=3834770
Physical memory (bytes) snapshot=28897976320
Virtual memory (bytes) snapshot=76076281856
Total committed heap usage (bytes)=24810881024
Shuffle Errors
BAD_ID=0
CONNECTION=0
IO_ERROR=0
WRONG_LENGTH=0
WRONG_MAP=0
WRONG_REDUCE=0
File Input Format Counters
Bytes Read=2637793709
File Output Format Counters
Bytes Written=10112132366
$ hadoop jar hadoop-mapreduce-examples-3.0.0-SNAPSHOT.jar wordcount -Dmapreduce.job.reduces=10 -Dmapreduce.job.map.output.collector.class=org.apache.hadoop.mapred.nativetask.NativeMapOutputCollectorDelegator wikimedia out1
(snip)
16/04/26 12:53:07 INFO mapreduce.Job: Counters: 51
File System Counters
FILE: Number of bytes read=14106605827
FILE: Number of bytes written=14111675351
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=2637796949
HDFS: Number of bytes written=10112132366
HDFS: Number of read operations=122
HDFS: Number of large read operations=0
HDFS: Number of write operations=20
Job Counters
Killed map tasks=3
Killed reduce tasks=1
Launched map tasks=24
Launched reduce tasks=11
Data-local map tasks=24
Total time spent by all maps in occupied slots (ms)=2159749
Total time spent by all reduces in occupied slots (ms)=3079008
Total time spent by all map tasks (ms)=2159749
Total time spent by all reduce tasks (ms)=1026336
Total vcore-milliseconds taken by all map tasks=2159749
Total vcore-milliseconds taken by all reduce tasks=1026336
Total megabyte-milliseconds taken by all map tasks=2211582976
Total megabyte-milliseconds taken by all reduce tasks=3152904192
Map-Reduce Framework
Map input records=185213309
Map output records=740850316
Map output bytes=17462982675
Map output materialized bytes=14106607147
Input split bytes=3240
Combine input records=945074830
Combine output records=0
Reduce input groups=84421738
Reduce shuffle bytes=14106607147
Reduce input records=178273190
Reduce output records=84421738
Spilled Records=560770894
Shuffled Maps =240
Failed Shuffles=0
Merged Map outputs=240
GC time elapsed (ms)=23530
CPU time spent (ms)=2119540
Physical memory (bytes) snapshot=23297888256
Virtual memory (bytes) snapshot=76028993536
Total committed heap usage (bytes)=23266852864
Shuffle Errors
BAD_ID=0
CONNECTION=0
IO_ERROR=0
WRONG_LENGTH=0
WRONG_MAP=0
WRONG_REDUCE=0
File Input Format Counters
Bytes Read=2637793709
File Output Format Counters
Bytes Written=10112132366
