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Hadoop, mail # user - Splitting files on new line using hadoop fs


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Mohit Anchlia 2012-02-22, 20:15
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bejoy.hadoop@... 2012-02-22, 20:23
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Mohit Anchlia 2012-02-22, 20:29
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Re: Splitting files on new line using hadoop fs
bejoy.hadoop@... 2012-02-22, 20:44
Hi Mohit
        I'm not an expert in pig and it'd be better using the pig user group for pig specific queries. I'd try to help you with some basic trouble shooting of the same

It sounds strange that pig's XML Loader can't load larger XML files that consists of multiple blocks. Or is it like, pig is not able to load the concatenated files that you are trying with? If that is the case then it could be because of some issues since you are just appending multiple xml file contents into a single file.

Pig users can give you some workarounds how they are dealing with loading of small xml files that are stored efficiently.

Regards
Bejoy K S

From handheld, Please excuse typos.

-----Original Message-----
From: Mohit Anchlia <[EMAIL PROTECTED]>
Date: Wed, 22 Feb 2012 12:29:26
To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Subject: Re: Splitting files on new line using hadoop fs

On Wed, Feb 22, 2012 at 12:23 PM, <[EMAIL PROTECTED]> wrote:

> Hi Mohit
>        AFAIK there is no default mechanism available for the same in
> hadoop. File is split into blocks just based on the configured block size
> during hdfs copy. While processing the file using Mapreduce the record
> reader takes care of the new lines even if a line spans across multiple
> blocks.
>
> Could you explain more on the use case that demands such a requirement
> while hdfs copy itself?
>

 I am using pig's XMLLoader in piggybank to read xml files concatenated in
a text file. But pig script doesn't work when file is big that causes
hadoop to split the files.

Any suggestions on how I can make it work? Below is my simple script that I
would like to enhance, only if it starts working. Please note this works
for small files.
register '/root/pig-0.8.1-cdh3u3/contrib/piggybank/java/piggybank.jar'

raw = LOAD '/examples/testfile5.txt using
org.apache.pig.piggybank.storage.XMLLoader('<abc>') as (document:chararray);

dump raw;

>
> ------Original Message------
> From: Mohit Anchlia
> To: [EMAIL PROTECTED]
> ReplyTo: [EMAIL PROTECTED]
> Subject: Splitting files on new line using hadoop fs
> Sent: Feb 23, 2012 01:45
>
> How can I copy large text files using "hadoop fs" such that split occurs
> based on blocks + new lines instead of blocks alone? Is there a way to do
> this?
>
>
>
> Regards
> Bejoy K S
>
> From handheld, Please excuse typos.
>

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Mohit Anchlia 2012-02-22, 22:57