Hi Abhay The map outputs are deleted only after the reducer runs to completion.
>Is it possible to run the same attempt again? Does killing the child java >process or tasktracker on the node help? (since hadoop may schedule a reduce >attempt on another node). Yes,it is possible to re attempt the task again for that you need to fail the current attempt. >Can I copy the map intermediate output required for this single reducer (which >is hanged) and rerun only the hang reducer? It is not that easy to accomplish this. Better fail the task explicitly so that the it is re attempted. Regards Bejoy KS Sent from handheld, please excuse typos. -----Original Message----- From: Abhay Ratnaparkhi <abhay.ratnapar...@gmail.com> Date: Tue, 28 Aug 2012 19:40:58 To: <user@hadoop.apache.org> Reply-To: user@hadoop.apache.org Subject: one reducer is hanged in "reduce-> copy" phase Hello, I have a MR job which has 4 reducers running. One of the reduce attempt is pending since long time in reduce->copy phase. The job is not able to complete because of this. I have seen that the child java process on tasktracker is running. Is it possible to run the same attempt again? Does killing the child java process or tasktracker on the node help? (since hadoop may schedule a reduce attempt on another node). Can I copy the map intermediate output required for this single reducer (which is hanged) and rerun only the hang reducer? Thank you in advance. ~Abhay ask_201208250623_0005_r_000000<http://dpep089.innovate.ibm.com:50030/taskdetails.jsp?tipid=task_201208250623_0005_r_000000> 26.41% reduce > copy(103 of 130 at 0.08 MB/s) 28-Aug-2012 03:09:34
