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From David Fang <f...@csl.cornell.edu>
Subject hadoop pipes C++ examples not reducing? [0.20.2]
Date Thu, 20 Jan 2011 17:46:03 GMT
 	[re-sent from common-user, since I haven't seen any responses]
 	New hadoop-0.20.2 user here.  Following directions in the c++ 
dirs, I've succesfully built and installed the C++ hadooppipes and 
hadooputils libraries on Mac OS X 10.6 (via configure; make), and compiled 
the various word-count example executables (also configure; make), and 
have also setup my hadoop dfs and environment, and -put some text files 
into the dfs's input directory.
 	When I run an example, however, wordcount-simple, the output dir
contains 2 part-* files (2 jobs), but I see no file that contains the
cumulative results of the two.  In other words, I think mapping is
happening, but reducing is not.
 	I am using the C++ pipes examples as-is from hadoop-0.20.2.  Is 
there something wrong with what I'm seeing?  What can I do to begin to 
debug this? FWIW, I was able to run the Java example WordCount.jar, and 
see a single output file with the cumulative results.
 	I also tried adding print statements (cout) to the wordcount
programs to see what's happening, but I don't see the effects of any
messages being logged anywhere.  Is there a way to effectively do
print-style debugging?

Thanks for any help!


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