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From: Michael Andrews <mandrews@liveops.com>
To: "core-user@hadoop.apache.org" <core-user@hadoop.apache.org>
Date: Thu, 7 Aug 2008 16:23:56 -0700
Subject: Re: Passing TupleWritable between map and reduce
Thread-Topic: Passing TupleWritable between map and reduce
Thread-Index: Acj449jhys3ScDHIl0uQYSwx+u5J6AAANCe8
Message-ID: <C4C0D21E.61%mandrews@liveops.com>
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Sorry about the massive code chunk, I am not used to this mail client, I at=
tached the file instead.

On 8/7/08 4:18 PM, "Michael Andrews" <mandrews@liveops.com> wrote:

Hi,

I am a new hadoop developer and am struggling to understand why I cannot pa=
ss TupleWritable between a map and reduce function.  I have modified the wo=
rdcount example to demonstrate the issue.  Also I am using hadoop 0.17.1.

Is properly constructing the desired tuple.  I am not sure if it is being o=
utputed correctly by output.collect as I cannot find the field in the Outpu=
tCollector data structure.  When I check in the reduce method the values ar=
e always empty tuples.  I have a feeling it has something to do with this l=
ine in the JavaDoc:

TupleWritable(Writable[] vals)
          Initialize tuple with storage; unknown whether any of them contai=
n "written" values.

Thanks in advance for any all help,

Michael


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