Hi,
I have also experienced this problem. Have you tried speculative execution?
Also, I have had jobs that took a long time for one mapper / reducer because of
a record that was significantly larger than those contained in the other
filesplits. Do you know if it always slows down for the same filesplit?
Regards,
Greg Lawrence
On 4/8/10 10:30 AM, "Raghava Mutharaju" <m.vijayaragh...@gmail.com> wrote:
Hello all,
I got the time out error as mentioned below -- after 600 seconds, that
attempt was killed and the attempt would be deemed a failure. I searched around
about this error, and one of the suggestions to include "progress" statements
in the reducer -- it might be taking longer than 600 seconds and so is timing
out. I added calls to context.progress() and context.setStatus(str) in the
reducer. Now, it works fine -- there are no timeout errors.
But, for a few jobs, it takes awfully long time to move from "Map
100%, Reduce 99%" to Reduce 100%. For some jobs its 15mins and for some it was
more than an hour. The reduce code is not complex -- 2 level loop and couple of
if-else blocks. The input size is also not huge, for the job that gets struck
for an hour at reduce 99%, it would take in 130. Some of them are 1-3 MB in
size and couple of them are 16MB in size.
Has anyone encountered this problem before? Any pointers? I use Hadoop
0.20.2 on a linux cluster of 16 nodes.
Thank you.
Regards,
Raghava.
On Thu, Apr 1, 2010 at 2:24 AM, Raghava Mutharaju <m.vijayaragh...@gmail.com>
wrote:
Hi all,
I am running a series of jobs one after another. While executing the 4th
job, the job fails. It fails in the reducer --- the progress percentage would
be map 100%, reduce 99%. It gives out the following message
10/04/01 01:04:15 INFO mapred.JobClient: Task Id :
attempt_201003240138_0110_r_000018_1, Status : FAILED
Task attempt_201003240138_0110_r_000018_1 failed to report status for 602
seconds. Killing!
It makes several attempts again to execute it but fails with similar message. I
couldn't get anything from this error message and wanted to look at logs
(located in the default dir of ${HADOOP_HOME/logs}). But I don't find any files
which match the timestamp of the job. Also I did not find history and userlogs
in the logs folder. Should I look at some other place for the logs? What could
be the possible causes for the above error?
I am using Hadoop 0.20.2 and I am running it on a cluster with 16 nodes.
Thank you.
Regards,
Raghava.
