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courses:mapreduce-tutorial:step-24 [2012/01/28 17:55]
straka |
courses:mapreduce-tutorial:step-24 [2012/01/30 15:04]
majlis |
| ===== Exercise ===== | ===== Exercise ===== |
| Download the ''MapperOnlyHadoopJob.java'', compile it and run it using | Download the ''MapperOnlyHadoopJob.java'', compile it and run it using |
| /net/projects/hadoop/bin/hadoop -r 0 MapperOnlyHadoopJob.jar /home/straka/wiki/cs-text-small outdir | wget --no-check-certificate 'https://wiki.ufal.ms.mff.cuni.cz/_export/code/courses:mapreduce-tutorial:step-24?codeblock=1' -O 'MapperOnlyHadoopJob.java' |
| | make -f /net/projects/hadoop/java/Makefile MapperOnlyHadoopJob.jar |
| | rm -rf step-24-out-sol; /net/projects/hadoop/bin/hadoop -r 0 MapperOnlyHadoopJob.jar /home/straka/wiki/cs-text-small step-24-out-sol |
| | less step-24-out-sol/part-* |
| |
| Mind the ''-r 0'' switch -- specifying ''-r 0'' disable the reducer. If the switch ''-r 0'' was not given, one reducer of default type ''IdentityReducer'' would be used. The ''IdentityReducer'' outputs every (key, value) pair it is given. | Mind the ''-r 0'' switch -- specifying ''-r 0'' disable the reducer. If the switch ''-r 0'' was not given, one reducer of default type ''IdentityReducer'' would be used. The ''IdentityReducer'' outputs every (key, value) pair it is given. |
