You are viewing a plain text version of this content. The canonical link for it is here.

Posted to common-user@hadoop.apache.org by Pramy Bhats <pr...@googlemail.com> on 2010/09/29 11:38:33 UTC

Reducers stucks in copy phase

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