Hi Oleg,
Speculative tasks can be launched as TaskAttempt in MR jobs.
And, if no reducer class is set, MR launches default Reducer
class(IdentityReducer).
Thanks,
Tsuyoshi
On Sun, Dec 9, 2012 at 11:53 PM, Oleg Zhurakousky
oleg.zhurakou...@gmail.com wrote:
I studying user logs on the two
MR launches multiple attempts for single Task in case of TaskAttempt failures
or when speculative execution is turned on. In either case, a given Task will
only ever have one successful TaskAttempt whose output will be accepted
(committed).
Number of reduces is set to 1 by default in
However, in the case Oleg is talking about the attempts are:
attempt_201212051224_0021_m_00_0
attempt_201212051224_0021_m_02_0
attempt_201212051224_0021_m_03_0
These aren't multiple attempts of a single task, are they ? They are
actually different tasks. If they were multiple
I studying user logs on the two node cluster that I have setup and I was
wondering if anyone can shed some light on these attempt*' directories
$ ls
attempt_201212051224_0021_m_00_0 attempt_201212051224_0021_m_03_0
job-acls.xml
attempt_201212051224_0021_m_02_0
