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Hadoop >> mail # user >> Very strange Java Collection behavior in Hadoop


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madhu phatak 2012-03-20, 05:52
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Owen OMalley 2012-03-20, 05:58
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madhu phatak 2012-03-20, 06:05
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Re: Very strange Java Collection behavior in Hadoop
On Mon, Mar 19, 2012 at 11:05 PM, madhu phatak <[EMAIL PROTECTED]> wrote:

> Hi Owen O'Malley,
>  Thank you for that Instant reply. It's working now. Can you explain me
> what you mean by "input to reducer is reused" in little detail?
Each time the statement "Text value = values.next();" is executed it always
returns the same Text object with the contents of that object changed. When
you add the Text to the list, you are adding a pointer to the same Text
object. At the end you have 6 copies of the same pointer instead of 6
different Text objects.

The reason that I said it is my fault, is because I added the optimization
that causes it. If you are interested in Hadoop archeology, it was
HADOOP-2399 that made the change. I also did HADOOP-3522 to improve the
documentation in the area.

-- Owen
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madhu phatak 2012-03-20, 07:42
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Milind.Bhandarkar@... 2012-03-21, 22:14
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Jay Vyas 2012-03-23, 06:38
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Jagat 2012-03-23, 06:42
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB