Hello guys:
I want to debug the map reduce tasks, especially
org.apache.hadoop.mapred.ReduceTask
I want to understand how the data flow work.
So I add the following in the mapred-site.xml
<property>
<name>mapred.child.java.opts</name>
<value>-Xdebug
-Xrunjdwp:transport=dt_socket,address=8888,server=y,suspend=y</value>
</property>
mapreduce.tasktracker.map.tasks.maximum 1
mapreduce.tasktracker.reduce.tasks.maximum 1
But by debugging JvmRunner, the -Xdebug is not added into the JVM start up
command.
Why? Is there some where guard this?
Or I have to build hadoop with my debug code?
Regards,
Skater
