will record having same key be sent to reducer at the same time

[Nick Cen <ce...@gmail.com>]

Hi all,

If i have a bunch of value that have the same key, and i have more then one
reducer running, which guarantee both mapper and reducer are running
concurently. Will all these value be send to the reducer at the same time?
Thx

-- 
http://daily.appspot.com/food/

Re: will record having same key be sent to reducer at the same time

[Nick Cen <ce...@gmail.com>]

Thanks.

2009/2/23 james warren <ja...@rockyou.com>

> Hi Nick -
> While your reducers may be running concurrently with your mappers, they
> will
> not begin the "sort" and "reduce" steps until all map tasks have completed.
>  Once they actually begin the reduce stage, they will have received all
> values for a given key.
>
> cheers,
> -jw
>
> On Mon, Feb 23, 2009 at 1:00 AM, Nick Cen <ce...@gmail.com> wrote:
>
> > Hi all,
> >
> > If i have a bunch of value that have the same key, and i have more then
> one
> > reducer running, which guarantee both mapper and reducer are running
> > concurently. Will all these value be send to the reducer at the same
> time?
> > Thx
> >
> > --
> > http://daily.appspot.com/food/
> >
>



-- 
http://daily.appspot.com/food/

Re: will record having same key be sent to reducer at the same time

[james warren <ja...@rockyou.com>]

Hi Nick -
While your reducers may be running concurrently with your mappers, they will
not begin the "sort" and "reduce" steps until all map tasks have completed.
 Once they actually begin the reduce stage, they will have received all
values for a given key.

cheers,
-jw

On Mon, Feb 23, 2009 at 1:00 AM, Nick Cen <ce...@gmail.com> wrote:

> Hi all,
>
> If i have a bunch of value that have the same key, and i have more then one
> reducer running, which guarantee both mapper and reducer are running
> concurently. Will all these value be send to the reducer at the same time?
> Thx
>
> --
> http://daily.appspot.com/food/
>