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在我的 MapReduce 作业完成后，我得到了大量的 Counter 信息:
File System Counters
FILE: Number of bytes read=4386096368
FILE: Number of bytes written=8805370803
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=54583718086
HDFS: Number of bytes written=4382090874
HDFS: Number of read operations=1479
HDFS: Number of large read operations=0
HDFS: Number of write operations=2
Job Counters
Launched map tasks=369
Launched reduce tasks=1
Data-local map tasks=369
Total time spent by all maps in occupied slots (ms)=34288552
Total time spent by all reduces in occupied slots (ms)=232084
Total time spent by all map tasks (ms)=8572138
Total time spent by all reduce tasks (ms)=58021
Total vcore-seconds taken by all map tasks=8572138
Total vcore-seconds taken by all reduce tasks=58021
Total megabyte-seconds taken by all map tasks=35111477248
Total megabyte-seconds taken by all reduce tasks=237654016
Map-Reduce Framework
Map input records=14753874
Map output records=666776
Map output bytes=4383426830
Map output materialized bytes=4386098552
Input split bytes=47970
Combine input records=0
Combine output records=0
Reduce input groups=1
Reduce shuffle bytes=4386098552
Reduce input records=666776
Reduce output records=666776
Spilled Records=1333552
Shuffled Maps =369
Failed Shuffles=0
Merged Map outputs=369
GC time elapsed (ms)=1121584
CPU time spent (ms)=23707900
Physical memory (bytes) snapshot=152915259392
Virtual memory (bytes) snapshot=2370755190784
Total committed heap usage (bytes)=126644912128
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=49449743227
File Output Format Counters
Bytes Written=4382090874
我在哪里可以找到每个字段的含义的解释？其中一些相当明显(读取的字节数)，但其他的则比较模糊(Total time by all maps in occupied slots vs Total time spent by all maps in occupied slots vs Total time spent by所有 map task )。
我找到了一个 list of all the default counters ，但我似乎找不到对它们的解释或描述。
令我感到相当惊讶的是，我似乎无法轻易找到有关此输出的文档。任何人都可以提供链接或解释吗？