hadoop-mapreduce-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Pedro Costa <psdc1...@gmail.com>
Subject Memory Manager in Hadoop MR
Date Thu, 09 Dec 2010 11:05:55 GMT

1 - Hadoop MR contains a TaskMemoryManagerThread class that is used to
manage memory usage of tasks running under a TaskTracker. Why Hadoop
MR needs a class to manage memory? Why it couldn't rely on the JVM, or
this class is here for another purpose?

2 - How the JT knows that a Map or Reduce Task finished? Is through
the heartbeat?



View raw message