Thanks! Mark On Wed, Feb 1, 2012 at 7:44 PM, Anil Gupta <[email protected]> wrote:
> Yes, if ur block size is 64mb. Btw, block size is configurable in Hadoop. > > Best Regards, > Anil > > On Feb 1, 2012, at 5:06 PM, Mark Kerzner <[email protected]> wrote: > > > Anil, > > > > do you mean one block of HDFS, like 64MB? > > > > Mark > > > > On Wed, Feb 1, 2012 at 7:03 PM, Anil Gupta <[email protected]> > wrote: > > > >> Do u have enough data to start more than one mapper? > >> If entire data is less than a block size then only 1 mapper will run. > >> > >> Best Regards, > >> Anil > >> > >> On Feb 1, 2012, at 4:21 PM, Mark Kerzner <[email protected]> > wrote: > >> > >>> Hi, > >>> > >>> I have a simple MR job, and I want each Mapper to get one line from my > >>> input file (which contains further instructions for lengthy > processing). > >>> Each line is 100 characters long, and I tell Hadoop to read only 100 > >> bytes, > >>> > >>> > >> > job.getConfiguration().setInt("mapreduce.input.linerecordreader.line.maxlength", > >>> 100); > >>> > >>> I see that this part works - it reads only one line at a time, and if I > >>> change this parameter, it listens. > >>> > >>> However, on a cluster only one node receives all the map tasks. Only > one > >>> map tasks is started. The others never get anything, they just wait. > I've > >>> added 100 seconds wait to the mapper - no change! > >>> > >>> Any advice? > >>> > >>> Thank you. Sincerely, > >>> Mark > >> >
