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MapReduce, mail # user - Please help on providing correct answers


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Ramasubramanian Narayanan... 2012-11-07, 17:21
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Michael Segel 2012-11-07, 17:27
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Ramasubramanian Narayanan... 2012-11-07, 17:30
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Re: Please help on providing correct answers
Michael Segel 2012-11-07, 18:37
Sorry, I think I had better explain why I am curious...

First, there are a couple of sites that have study questions to help pass Cloudera's certification.
( I don't know if Hortonworks has cert tests, but both MapR and Cloudera do.)

Its just looking first at the questions... not really good questions and selection of answers.  Then the 'correct' answer.

I can understand if you don't want to reveal your sources publicly, but you have to understand that misinformation found in these sites makes it harder to teach the right answers.

As Harsh says, you should be able to look at the questions and then go back to Tom White's book and others to verify why you think your answer is right.

HTH

-Mike

On Nov 7, 2012, at 11:30 AM, Ramasubramanian Narayanan <[EMAIL PROTECTED]> wrote:

> nothing as consolidated...... I am collecting for the past 1 month... few as printout and few from mails and few from googling and few from sites and few from some of my friends...
>
> regards,
> Rams
>
> On Wed, Nov 7, 2012 at 10:57 PM, Michael Segel <[EMAIL PROTECTED]> wrote:
> Ok...
> Where are you pulling these questions from?
>
> Seriously.
>
>
> On Nov 7, 2012, at 11:21 AM, Ramasubramanian Narayanan <[EMAIL PROTECTED]> wrote:
>
> > Hi,
> >
> >    I came across the following question in some sites and the answer that they provided seems to be wrong according to me... I might be wrong... Can some one help on confirming the right answers for these 11 questions pls.. appreciate the explanation if you could able to provide...
> >
> > *******************************************************************************
> > You are running a job that will process a single InputSplit on a cluster which has no other jobs
> > currently running. Each node has an equal number of open Map slots. On which node will Hadoop
> > first attempt to run the Map task?
> > A. The node with the most memory
> > B. The node with the lowest system load
> > C. The node on which this InputSplit is stored
> > D. The node with the most free local disk space
> >
> > My Answer            : C
> > Answer Given in site : A
> >
> > *******************************************************************************
> > What is a Writable?
> > A. Writable is an interface that all keys and values in MapReduce must implement. Classes implementing this interface must implement methods forserializingand deserializing themselves.
> > B. Writable is an abstract class that all keys and values in MapReduce must extend. Classes extending this abstract base class must implementmethods for serializing and deserializingthemselves
> > C. Writable is an interface that all keys, but not values, in MapReduce must implement. Classes implementing this interface mustimplementmethods for serializing and deserializing themselves.
> > D. Writable is an abstract class that all keys, but not values, in MapReduce must extend. Classes extending this abstract base class must implementmethods for serializing and deserializing themselves.
> >
> > My Answer            : A
> > Answer Given in site : B
> >
> > *******************************************************************************
> >
> > You write a MapReduce job to process 100 files in HDFS. Your MapReducc algorithm uses
> > TextInputFormat and the IdentityReducer: the mapper applies a regular expression over input
> > values and emits key-value pairs with the key consisting of the matching text, and the value
> > containing the filename and byte offset. Determine the difference between setting the number of
> > reducers to zero.
> > A. There is no differenceinoutput between the two settings.
> > B. With zero reducers, no reducer runs and the job throws an exception. With one reducer,
> > instances of matching patterns are stored in a single file on HDFS.
> > C. With zero reducers, all instances of matching patterns are gathered together in one file on
> > HDFS. With one reducer, instances ofmatching patternsstored in multiple files on HDFS.
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Ramasubramanian Narayanan... 2012-11-07, 18:54