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courses:mapreduce-tutorial:step-7 [2012/01/29 20:51] straka |
courses:mapreduce-tutorial:step-7 [2012/01/31 09:41] straka Change Perl commandline syntax. |
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===== Using a running cluster ===== | ===== Using a running cluster ===== | ||
Running cluster is identified by its master. When running a Hadoop job using Perl API, existing cluster can be used by | Running cluster is identified by its master. When running a Hadoop job using Perl API, existing cluster can be used by | ||
- | perl script.pl | + | perl script.pl -jt cluster_master: |
===== Example ===== | ===== Example ===== | ||
Line 18: | Line 18: | ||
wget --no-check-certificate ' | wget --no-check-certificate ' | ||
/ | / | ||
- | rm -rf step-7-out-sol; | + | |
+ | # $EDITOR step-7-wordcount.pl | ||
+ | | ||
less less step-7-out-sol/ | less less step-7-out-sol/ | ||
Remarks: | Remarks: | ||
- | * The reducers seem to start running before the mappers | + | * The reducers seem to start running before the mappers |
+ | * during the first 33%, the mapper outputs are copied | ||
+ | * during the second 33%, the (key, value) pairs are sorted. | ||
+ | * during the last 33%, the user-defined reducer runs. | ||
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