In the Reducer.class, you could ignore the data that you want to exclude based on the key or value.
> On Mar 12, 2015, at 12:47 PM, xeonmailinglist-gmail > <xeonmailingl...@gmail.com> wrote: > > If I use the partitioner, I must be able to tell map reduce to not execute > values from a certain reduce tasks. > > The method public int > getPartition(K key, V value, int numReduceTasks) must always return > a partition. I can’t return -1. Thus, I don’ t know how to tell Mapreduce to > not execute data from a partition. Any suggestion? > > ———— Forwarded Message ———— > > Subject: Re: Prune out data to a specific reduce task > > Date: Thu, 12 Mar 2015 12:40:04 -0400 > > From: Fei Hu hufe...@gmail.com <http://mailto:hufe...@gmail.com/> > Reply-To: user@hadoop.apache.org <mailto:user@hadoop.apache.org> > To: user@hadoop.apache.org <mailto:user@hadoop.apache.org> > Maybe you could use Partitioner.class to solve your problem. > > > >> On Mar 11, 2015, at 6:28 AM, xeonmailinglist-gmail >> <xeonmailingl...@gmail.com <mailto:xeonmailingl...@gmail.com>> wrote: >> >> Hi, >> >> I have this job that has 3 map tasks and 2 reduce tasks. But, I want to >> excludes data that will go to the reduce task 2. This means that, only >> reducer 1 will produce data, and the other one will be empty, or even it >> doesn't execute. >> >> How can I do this in MapReduce? >> >> <ExampleJobExecution.png> >> >> >> Thanks, >> >> -- >> -- > >
