英文:
System.out.println in Hadoop Driver Class
问题
我想测量Hadoop作业执行的时间。在我的Driver类中，我有：
long start = System.currentTimeMillis();
long end = System.currentTimeMillis();
System.out.println(end - start);
但是Hadoop把System.out.println()发送到哪里呢？
编辑
当程序结束时，终端会打印出作业计数器，我能否获得总执行时间如下：
Total execution time = 所有映射任务在占用槽中花费的总时间 + 所有减少任务在占用槽中花费的总时间 + 所有映射任务花费的总时间 + 所有减少任务花费的总时间？
英文:
I want to measure time to Hadoop job to execute. In my Driver class I have:
long start = System.currentTimeMillis();
long end = System.currentTimeMillis();
System.out.println(end-start);
But where does hadoop send the System.out.println()?
EDIT
When the program ends the terminal prints out Job Counters, can I get the total execution time as:
Total execution time = Total time spent by all maps in occupied slots + Total time spent by all reduces in occupied slots + Total time spent by all maps task + Total time spent by all reduces task ?
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