Thnaks Hemanth On Fri, Oct 22, 2010 at 10:09 PM, Hemanth Yamijala <yhema...@gmail.com>wrote:
> Hi, > > Apologies for a very delayed response. > > The setup task is under the control of the user, and the user can > provide an implementation that makes sense for his/her M/R job. That > said, like with other APIs in M/R, there is an implementation that > comes in the library for the common use cases. For e.g. the setup task > sets up the 'temporary' output directory on HDFS into which tasks > write their output. > > The M/R documentation has more information and you could refer to that. > > Hope that helps. > Hemanth > > On Thu, Oct 14, 2010 at 10:11 AM, He Chen <airb...@gmail.com> wrote: > > Hi Hemanth > > > > Thank you for your kindly reply. Do you know what really the setup do? > Does > > it will take the data locality into account? > > > > On Wed, Oct 13, 2010 at 11:38 PM, Hemanth Yamijala <yhema...@gmail.com > >wrote: > > > >> If you are talking about the 'Setup task' that is used to initialize > >> or setup the job, yes, it can run on either the map slot or reduce > >> slot depending on what is available. > >> > >> Thanks > >> Hemanth > >> > >> On Thu, Oct 14, 2010 at 1:54 AM, He Chen <airb...@gmail.com> wrote: > >> > Hi, all > >> > > >> > I found out that if the there is no map slot, Hadoop will use reduce > slot > >> to > >> > setup mapreduce job when I submit a series of jobs. > >> > > >> > The first two jobs setuped themselves with a MapAttempt. However, they > >> > occupy all the map slots. When the third job comes, I find out it uses > >> the > >> > ReduceAttempt to du the setup. After that, no more setup logged in the > >> job > >> > history. > >> > > >> > Am I correct? > >> > > >> > > >> > Chen > >> > > >> > > >
