If you need another shuffle after your first reduce pass, then you need a second MapReduce job to run after the first one. Just use an IdentityMapper.
This is a reasonably common situation. - Aaron On Thu, Oct 22, 2009 at 4:17 PM, Forhadoop <rutu...@gmail.com> wrote: > > Hello, > > In my application I need to reduce the original reducer output keys > further. > > I was reading about Chainreducer and Chainmappers but looks like it is for > : > one or more mapper -> reducer -> 0 or more mappers > > I need something like: > one or more mapper -> reducer -> reducer > > Please help me figure out the best way to achieve it. Currently, the only > options seems like I write another map reduce application and run it > separately after the first map-reduce application. In this second > application, the mapper will be dummy and won't do anything. The reducer > will further club the first run outputs. > > Any other comments such as this is not a good programming practice are > welcome, so that I know I am in the wrong direction.. > -- > View this message in context: > http://www.nabble.com/Can-I-have-multiple-reducers--tp26018722p26018722.html > Sent from the Hadoop core-user mailing list archive at Nabble.com. >
