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From Ted Xu <...@gopivotal.com>
Subject Re: Warnings?
Date Sat, 27 Apr 2013 00:49:31 GMT

First warning is saying hadoop cannot load native library, usually a
compression codec. In that case, hadoop will use java implementation
instead, which is slower.

Second is caused by hadoop 1.x/2.x configuration key change. You're using a
1.x style key under 2.x, yet hadoop still guarantees backward compatibility.

Third is saying that the main class of a hadoop application is recommanded
to implement org.apache.hadoop.util.Tool<http://hadoop.apache.org/docs/current/api/org/apache/hadoop/util/Tool.html>,
or else generic command line options (e.g., -D options) will not supported.

On Sat, Apr 27, 2013 at 5:51 AM, <rkevinburton@charter.net> wrote:

> I am running a simple WordCount m/r job and I get output but I get five
> warnings that I am not sure if I should pay attention to:
> *13/04/26 16:24:50 WARN util.NativeCodeLoader: Unable to load
> native-hadoop library for your platform... using builtin-java classes where
> applicable *
> *13/04/26 16:24:50 WARN conf.Configuration: session.id is deprecated.
> Instead, use dfs.metrics.session-id *
> *13/04/26 16:24:50 WARN mapred.JobClient: Use GenericOptionsParser for
> parsing the arguments. Applications should implement Tool for the same. *
> *13/04/26 16:24:51 WARN mapreduce.Counters: Group
> org.apache.hadoop.mapred.Task$Counter is deprecated. Use
> org.apache.hadoop.mapreduce.TaskCounter instead *
> *13/04/26 16:24:51 WARN mapreduce.Counters: Counter name MAP_INPUT_BYTES
> is deprecated. Use FileInputFormatCounters as group name and  BYTES_READ as
> counter name instead*
> Any ideas on what these mean? The only one that I can see in the code is
> the third one. I am using GenericOptionsParser as it is part of an example
> that I copied. But I don't know why this is considered bad.
> Thank you.

Ted Xu

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