Vitaliy Semochkin 2010-07-28, 19:24
-Re: what affects number of reducers launched by hadoop?
Ted Yu 2010-07-28, 19:33
The 3 stages for reducer are:
On Wed, Jul 28, 2010 at 12:24 PM, Vitaliy Semochkin <[EMAIL PROTECTED]>wrote:
> in my cluster mapred.tasktracker.reduce.tasks.maximum = 4
> however during monitoring the job in job tracker I see only 1 reducer
> first it is
> reduce > copy - can someone please explain what does this mean?
> after it is
> reduce > reduce
> when I set the number of reduce tasks for a job programatically to 10
> the number of "reduce > reduce" reducers increases to 10 and the
> performance of application increases as well (the number of reducers
> never exceeds).
> Can someone explain such behavior?
> Thanks in Advance,
> Vitaliy S
Joe Stein 2010-07-28, 19:40
Abhinay Mehta 2010-07-29, 10:31
Vitaliy Semochkin 2010-07-29, 11:20
Raj V 2010-07-29, 16:37
Joe Stein 2010-07-29, 12:54