Hi, While trying to run a MapReduce job, the reducers stucks in the copy phase indefinitely. Though, all the Mapper have been finished the reducers stucks at 15-20% completion.
The log available at the Reducers is as follows: 2010-09-29 11:33:24,535 INFO org.apache.hadoop.mapred.ReduceTask: attempt_201009291127_0001_r_000000_0 Need another 7 map output(s) where 5 is already in progress 2010-09-29 11:33:24,535 INFO org.apache.hadoop.mapred.ReduceTask: attempt_201009291127_0001_r_000000_0 Scheduled 0 outputs (0 slow hosts and2 dup hosts) 2010-09-29 11:34:24,536 INFO org.apache.hadoop.mapred.ReduceTask: attempt_201009291127_0001_r_000000_0 Need another 7 map output(s) where 5 is already in progress 2010-09-29 11:34:24,536 INFO org.apache.hadoop.mapred.ReduceTask: attempt_201009291127_0001_r_000000_0 Scheduled 0 outputs (0 slow hosts and2 dup hosts) 2010-09-29 11:35:24,537 INFO org.apache.hadoop.mapred.ReduceTask: attempt_201009291127_0001_r_000000_0 Need another 7 map output(s) where 5 is already in progress 2010-09-29 11:35:24,537 INFO org.apache.hadoop.mapred.ReduceTask: attempt_201009291127_0001_r_000000_0 Scheduled 0 outputs (0 slow hosts and2 dup hosts) Could you please help me to figure the cause of this reducers stall ? thanks in advance. --PB
