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From Viji R <v...@cloudera.com>
Subject Re: 2 Map tasks running for a small input file
Date Thu, 26 Sep 2013 11:09:37 GMT
Hi,

Default number of map tasks is 2. You can set mapred.map.tasks to 1 to
avoid this.

Regards,
Viji

On Thu, Sep 26, 2013 at 4:28 PM, Sai Sai <saigraph@yahoo.in> wrote:
> Hi
> Here is the input file for the wordcount job:
> ******************
> Hi This is a simple test.
> Hi Hadoop how r u.
> Hello Hello.
> Hi Hi.
> Hadoop Hadoop Welcome.
> ******************
>
> After running the wordcount successfully
> here r the counters info:
>
> ***************
> Job Counters SLOTS_MILLIS_MAPS 0 0 8,386
> Launched reduce tasks 0 0 1
> Total time spent by all reduces waiting after reserving slots (ms) 0 0 0
> Total time spent by all maps waiting after reserving slots (ms) 0 0 0
> Launched map tasks 0 0 2
> Data-local map tasks 0 0 2
> SLOTS_MILLIS_REDUCES 0 0 9,199
> ***************
> My question why r there 2 launched map tasks when i have only a small file.
> Per my understanding it is only 1 block.
> and should be only 1 split.
> Then for each line a map computation should occur
> but it shows 2 map tasks.
> Please let me know.
> Thanks
> Sai
>

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