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MapReduce >> mail # user >> Can reducer get parameters from mapper besides key and value?


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谭军 2011-08-09, 06:28
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Subroto Sanyal 2011-08-09, 06:42
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谭军 2011-08-09, 06:55
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RE: RE: Can reducer get parameters from mapper besides key and value?
Hi Jun

 

I mean that if I get some strings in mapper and I want to use them in
reducer.

But they are neither keys nor values.

As per my understanding, there is no such way to pass an arbitrary reference
from Mapper to Reducer.

The information written in Output from Mapper is available to Reducer.

Further more, I don’t feel it will be good idea to keep such dependency.

Please let me know more about your scenario…may be we/community can suggest
some solution…

 

By the way, Can reducer get side files in cache?

Please let me know about “Side Files”…..

 

Regards,
Subroto Sanyal

  _____  

From: 谭军 [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, August 09, 2011 12:25 PM
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: Re:RE: Can reducer get parameters from mapper besides key and
value?

 

Hi Subroto,

I mean that if I get some strings in mapper and I want to use them in
reducer.

But they are neither keys nor values.

 

By the way, Can reducer get side files in cache?

 

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Regards!

Jun Tan
At 2011-08-09 14:42:10,"Subroto Sanyal" <[EMAIL PROTECTED]> wrote:

 

Hi Jun,

 

What is the file, list, string [] in this context?

I mean to say which file or list or string[].

 

The new MR (org.apache.hadoop.mapreduce.*) APIs has a parameter “context”.
Request you to browse through the APIs of Context (Inherited from
JobContext->TaskAttemptContext).

The context parameter may provide you the reference you need.

 

Regards,
Subroto Sanyal

  _____  

From: 谭军 [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, August 09, 2011 11:58 AM
To: mapreduce
Subject: Can reducer get parameters from mapper besides key and value?

 

Hi,

Can reducer gets parameters from mapper besides key and value?

Such as files, lists, string[] etc.

Thanks
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Regards!

Jun Tan


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谭军 2011-08-09, 11:53
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Subroto Sanyal 2011-08-09, 13:41
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谭军 2011-08-09, 14:09
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谭军 2011-08-09, 14:31
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Subroto Sanyal 00900485 2011-08-09, 18:51
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谭军 2011-08-14, 13:25