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MapReduce, mail # user - System.out.println in Map / Reduce


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Arko Provo Mukherjee 2011-09-26, 23:47
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Joey Echeverria 2011-09-27, 00:49
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RE: System.out.println in Map / Reduce
Subroto Sanyal 2011-09-27, 03:18
Hi Arko,

 

Request you to look into the "userlogs" folder of the corresponding task.

It will have three file sysout, syslog and syserr. Your System.out.println()
will be captured in these files.

The usual location for "userlogs" folder is "${HADOOP_LOG_DIR}/userlogs".

 

>From MapReduce tutorial at:
http://hadoop.apache.org/common/docs/r0.18.3/mapred_tutorial.html

 

*The standard output (stdout) and error (stderr) streams of the task are
read by the TaskTracker and logged to ${HADOOP_LOG_DIR}/userlogs *

 

Regards,
Subroto Sanyal

  _____  

From: Arko Provo Mukherjee [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, September 27, 2011 5:18 AM
To: [EMAIL PROTECTED]
Subject: System.out.println in Map / Reduce

 

Hi,

 

I am writing some Map Reduce programs in pseudo-distributed mode.
I am getting some error in my program and would like to debug it.

 

For that I want to embed some print statements in my Map / Reduce.

 

But when I am running the mappers, the prints doesn't seem to show up in the
terminal.

 

Does the mappers / reducers redirect the prints to some files or are they
suppressed or it is a problem with my program?

 

Many thanks in advance!

Thanks & regards

Arko

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Arko Provo Mukherjee 2011-09-27, 15:58