Each mapper is already running in its own JVM. Maybe if you explain why you want to start threads someone might have some suggestions. (If at all possible I suggest you avoid doing that) Chris On Dec 11, 2013 6:26 AM, "Ranjini Rathinam" <[email protected]> wrote:
> Hi, > > I am fresher to mapreduce concept, > I would like to know how to implement multithread concept in mapreduce. > > Please provide sample program for implementating the above concept. > > Thanks in advance. > Ranjini.R > > On Mon, Dec 9, 2013 at 12:34 PM, Ranjini Rathinam > <[email protected]>wrote: > >> hi, >> >> Will these class support in hadoop 0.20 version. I am using this only.? >> >> Please suggest. >> >> Thanksin advance, >> >> Ranjini.R >> >> On Mon, Dec 9, 2013 at 12:27 PM, Vinayakumar B <[email protected] >> > wrote: >> >>> Hi Ranjini, >>> >>> >>> >>> Please check this mapper class whether this suites your needs. >>> >>> org.apache.hadoop.mapreduce.lib.map.MultithreadedMapper >>> >>> >>> >>> Thanks and Regards, >>> >>> Vinayakumar B >>> >>> *From:* Ranjini Rathinam [mailto:[email protected]] >>> *Sent:* 09 December 2013 11:13 >>> *To:* [email protected] >>> *Subject:* Re: hadoop -Mapreduce >>> >>> >>> >>> HI, >>> >>> >>> >>> I need to use thread functionality to run more than one mapper class >>> parallelly. >>> >>> >>> >>> Please suggest with some sample code. >>> >>> >>> >>> Thanks in advance. >>> >>> On Fri, Dec 6, 2013 at 4:37 PM, Subroto <[email protected]> wrote: >>> >>> Hi Ranjini, >>> >>> >>> >>> The number of mappers depend on InputSplits and which intern depends on >>> size of input data. >>> >>> The number of reducers can be configured by "mapred.reduce.tasks" >>> >>> >>> >>> Further you can get more information on numbers of Maps and Reduce for a >>> Job from: >>> >>> http://wiki.apache.org/hadoop/HowManyMapsAndReduces >>> >>> >>> >>> Running parallel mappers and reducers depends on availability of map and >>> reduce slots in the cluster. >>> >>> >>> >>> Cheers, >>> >>> Subroto Sanyal >>> >>> >>> >>> On Dec 6, 2013, at 12:00 PM, Ranjini Rathinam wrote: >>> >>> >>> >>> HI, >>> >>> >>> >>> How to run more than one mapper and reduce parallelly.? >>> >>> >>> >>> Please suggest.Thanks in advance. >>> >>> >>> >>> Ranjini. >>> >>> >>> >>> >>> >> >> >
