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From Jeff Zhang <zjf...@gmail.com>
Subject Re: only one reduce task?
Date Fri, 04 Dec 2009 00:32:01 GMT
Mike,

Do you mean you only have one reducer task for a Job ?

You can increase the number of reducer task for one Job by setting

JobConf.setNumReduceTasks(n)


Jeff Zhang


On Thu, Dec 3, 2009 at 2:58 PM, Mike Kendall <mkendall@justin.tv> wrote:

> i can't seem to get my cluster to run more than one reduce task...  my
> mapred-site.xml looks like this:
>
> <?xml version="1.0"?>
> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
>
> <!-- Put site-specific property overrides in this file. -->
> <configuration>
> <property>
>  <name>mapred.job.tracker</name>
>  <value>master:9001</value>
> </property>
> <property>
>  <name>mapred.tasktracker.map.tasks.maximum</name>
>  <value>5</value>
> </property>
>
> <property>
>  <name>mapred.tasktracker.reduce.tasks.maximum</name>
>  <value>5</value>
> </property>
> <property>
>  <name>mapred.map.tasks</name>
>  <value>40</value>
> </property>
> <property>
>  <name>mapred.reduce.tasks</name>
>  <value>8</value>
> </property>
> <property>
>  <name>mapred.jobtracker.taskScheduler</name>
>  <value>org.apache.hadoop.mapred.FairScheduler</value>
> </property>
> <property>
>  <name>mapred.fairscheduler.allocation.file</name>
>  <value>/usr/local/hadoop/conf/fairshare-pools.xml</value>
> </property>
> </configuration>
>
> any ideas?  thanks.
>

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