解读：计数器Counter
http://www.cnblogs.com/codeOfLife/p/5521356.html 这个讲的更详细
17/05/23 17:18:53 INFO mapreduce.Job: Counters: 49 # 6类（）49个计数器（亲自数了一遍）。 File System Counters FILE: Number of bytes read=12222 FILE: Number of bytes written=239539 FILE: Number of read operations=0 FILE: Number of large read operations=0 FILE: Number of write operations=0 HDFS: Number of bytes read=11316 HDFS: Number of bytes written=1892 HDFS: Number of read operations=8 HDFS: Number of large read operations=0 HDFS: Number of write operations=2 Job Counters Launched map tasks=1 Launched reduce tasks=1 Other local map tasks=1 Total time spent by all maps in occupied slots (ms)=21775 Total time spent by all reduces in occupied slots (ms)=16960 Total time spent by all map tasks (ms)=21775 Total time spent by all reduce tasks (ms)=16960 Total vcore-milliseconds taken by all map tasks=21775 Total vcore-milliseconds taken by all reduce tasks=16960 Total megabyte-milliseconds taken by all map tasks=22297600 Total megabyte-milliseconds taken by all reduce tasks=17367040 Map-Reduce Framework Map input records=108 Map output records=216 Map output bytes=11784 Map output materialized bytes=12222 Input split bytes=279 Combine input records=0 Combine output records=0 Reduce input groups=36 Reduce shuffle bytes=12222 Reduce input records=216 Reduce output records=36 Spilled Records=432 Shuffled Maps =1 Failed Shuffles=0 Merged Map outputs=1 GC time elapsed (ms)=232 CPU time spent (ms)=2180 Physical memory (bytes) snapshot=273268736 Virtual memory (bytes) snapshot=4118401024 Total committed heap usage (bytes)=137498624 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=0 File Output Format Counters Bytes Written=1892