Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
Hadoop >> mail # user >> Very strange Java Collection behavior in Hadoop


Copy link to this message
-
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