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From Harsh J <ha...@cloudera.com>
Subject Re: mapred.child.java.opts and mapreduce.reduce.java.opts
Date Mon, 02 Apr 2012 11:55:30 GMT
For 1.0, the right property is "mapred.reduce.child.java.opts". The
"mapreduce.*" style would apply to MR in 2.0 and above.

On Mon, Apr 2, 2012 at 3:00 PM, Juan Pino <juancitomiguelito@gmail.com> wrote:
> Hello,
> I have a job that requires a bit more memory than the default for the
> reducer (not for the mapper).
> So for this I have this property in my configuration file:
> mapreduce.reduce.java.opts=-Xmx4000m
> When I run the job, I can see its configuration in the web interface and I
> see that indeed I have mapreduce.reduce.java.opts set to -Xmx4000m
> but I also have mapred.child.java.opts set to -Xmx200m and when I ps -ef
> the java process, it is using -Xmx200m.
> So to make my job work I had to set mapred.child.java.opts=-Xmx4000m in my
> configuration file.
> However I don't need that much memory for the mapper.
> How can I set more memory only for the mapper ? Is the only solution to set
> mapred.child.java.opts to -Xmx4000m, mapreduce.reduce.java.opts to -Xmx4000m
> and mapreduce.map.java.opts to -Xmx200m ?
> I am using hadoop 1.0.1.
> Thank you very much,
> Juan

Harsh J

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