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Locked Map Tasks

Question asked by andrew_wells on Aug 10, 2011
Latest reply on Aug 11, 2011 by andrew_wells
I am stumped now. I am attempting to perform TeraSort. To speed it up, I am increasing the number of map and reduce tasks. However after a while the map tasks seem to lockup, I thought the reducers might be locking some of them out, so I reduce the number of reduce tasks. Still locked up. I eventually set mapred.reduce.slowstart.completed.maps=1 so that the map tasks had to complete before any reduce tasks started. I am now have one map task that is pending, none running, with an average of 20 seconds to run. This task has been waiting for 20 minutes to run and no one else is using the cluster.

Whats up?

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