1
我在一个模板配置文件中看到了这些:Hadoop推荐素数的map/reduce任务?
<property>
<name>mapred.map.tasks</name>
<value>2</value>
<description>The default number of map tasks per job. Typically set
to a prime several times greater than number of available hosts.
Ignored when mapred.job.tracker is "local".
</description>
</property>
...
<property>
<name>mapred.reduce.tasks</name>
<value>1</value>
<description>The default number of reduce tasks per job. Typically set
to a prime close to the number of available hosts. Ignored when
mapred.job.tracker is "local".
</description>
</property>
我找不到任何其他的参考,无论是在网上还是在Hadoop的O'Reilly出版的书,为什么这些应该是素。有人有主意吗?
谢谢。