Hi all,
I am trying to run terasort using one map and one reduce. so, I generated
the input data using:
hadoop jar hadoop-examples-1.0.4.jar teragen -Dmapred.map.tasks=1
-Dmapred.reduce.tasks=1 32000000 /user/hadoop/input32mb1map
Then I launched the hadoop terasort job using:
hadoop jar hadoop-examples-1.0.4.jar terasort -Dmapred.map.tasks=1
-Dmapred.reduce.tasks=1 /user/hadoop/input32mb1map /user/hadoop/output1
I thought it will run the job using 1 map and 1 reduce, but when inspect
the job statistics I found:
hadoop job -history /user/hadoop/output1
Task Summary
============================
Kind Total Successful Failed Killed StartTime FinishTime
Setup 1 1 0 0 26-Feb-2013 10:57:47 26-Feb-2013
10:57:55 (8sec)
Map 24 24 0 0 26-Feb-2013 10:57:57 26-Feb-2013
11:05:37 (7mins, 40sec)
Reduce 1 1 0 0 26-Feb-2013 10:58:21 26-Feb-2013
11:08:31 (10mins, 10sec)
Cleanup 1 1 0 0 26-Feb-2013 11:08:32 26-Feb-2013
11:08:36 (4sec)
============================
so, though I mentioned to launch one map tasks, there are 24 of them.
How to solve this problem. How to tell hadoop to launch only one map.
Thanks,
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