I still would like to know how many times it will run given how many mappers run. I realize it may never run but what determines how many times if any?
--- On Fri, 12/4/09, Mike Kendall <[email protected]> wrote: > From: Mike Kendall <[email protected]> > Subject: Re: Combiner phase question > To: [email protected] > Date: Friday, December 4, 2009, 4:59 PM > are you sure it can be run in the > reduce task? if it does it's still > before the reducer is called though... so the flow of > your data will > still be: data -> mapper(s) -> optional reducer(s) > -> reducer(s) -> > output_data > > > > On Fri, Dec 4, 2009 at 1:42 PM, Owen O'Malley <[email protected]> > wrote: > > On Fri, Dec 4, 2009 at 12:32 PM, Raymond Jennings III > <[email protected] > >> wrote: > > > >> Does the combiner run once per data node or one > per map task? (That it can > >> run multiple times on the same data node after > each map task.) Thanks. > >> > > > > The combiner can run 0, 1, or many times on each data > value. It can run in > > both the map task and reduce task. > > > > -- Owen > > >
