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MapReduce, mail # user - Re: output/input ratio > 1 for map tasks?


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Re: output/input ratio > 1 for map tasks?
Niels Basjes 2012-07-30, 20:15
Hi,

On Mon, Jul 30, 2012 at 8:47 PM, brisk <[EMAIL PROTECTED]> wrote:
> Does anybody know if there are some cases where the output/input ratio for
> map tasks is larger than 1? I can just think of for the sort, it's 1 and for
> the search job it's usually smaller than 1...

For a simple example: Have a look at the WordCount example.

Input of a single map call is 1 record: "This is a line"
Output are 4 records:
This    1
is       1
a        1
line     1

--
Best regards / Met vriendelijke groeten,

Niels Basjes