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From Adam Pridgen <adam.prid...@thecoverofnight.com>
Subject Re: Printing Debug Messages and Setting up Mapper Classes Programmatically
Date Wed, 09 Feb 2011 05:45:39 GMT
Thanks for your help.  I will look at log4j.

-- Adam

sent from a mobile phone.
On Feb 8, 2011 7:01 PM, "Harsh J" <qwertymaniac@gmail.com> wrote:
> Hello,
>
> On Wed, Feb 9, 2011 at 6:33 AM, Adam Pridgen
> <adam.pridgen@thecoverofnight.com> wrote:
>> Hello,
>>
>> I am trying to setup my Mapper class before it is set-up to run as a
>> task.  Specifically, I am trying to override the method
>> Mapper.setup(Mapper.Context).  When I run the MapReduce program I am
>> expecting an output to stdout of about about 6 lines along with the
>> configuration information read out of the Context.  I have two
>> questions:
>>
>> --- Am I correctly setting up the mapper set task?
>
> Yes, @Overriding the setup method is the right way to do this with the
> new Mapper API.
>
>> --- Do I need to print/debug messages through an API of some sort, or
>> is printing output to stdout OK?
>
> While stdout is okay to use, and the outputs of that do get stored in
> stdout/stderr files of the Task on the TaskTracker machine, it makes
> more sense to use a logger API instead for debugging purposes for
> automatic time-stamps, levels of severity, classnames, etc.. Much more
> easier to replay logger outputs in mind than stdouts while debugging.
>
> Hadoop comes with commons-logging and log4j libraries for use
out-of-the-box.
>
> --
> Harsh J
> www.harshj.com

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