The Mapper and Reducer interfaces both provide a method 'void configure(JobConf conf) throws IOException'; if you extend MapReduceBase, this will provide a dummy implementation of configure(). You can add your own implementation; it will be called before the first call to map() or reduce(). You can read your initialization data at this time.
- Aaron On Thu, Oct 30, 2008 at 4:02 PM, Erik Holstad <[EMAIL PROTECTED]> wrote: > Hi! > Is there a way of using the value read in the configure() in the Map or > Reduce phase? > > Erik > > On Thu, Oct 23, 2008 at 2:40 AM, Aaron Kimball <[EMAIL PROTECTED]> wrote: > > > See Configuration.setInt() in the API. (JobConf inherits from > > Configuration). You can read it back in the configure() method of your > > mappers/reducers > > - Aaron > > > > On Wed, Oct 22, 2008 at 3:03 PM, Yih Sun Khoo <[EMAIL PROTECTED]> wrote: > > > > > Are you saying that I can pass, say, a single integer constant with > > either > > > of these three: JobConf? A HDFS file? DistributedCache? > > > Or are you asking if I can pass given the context of: JobConf? A HDFS > > file? > > > DistributedCache? > > > I'm thinking of how to pass a single int so from one Jobconf to the > next > > > > > > On Wed, Oct 22, 2008 at 2:57 PM, Arun C Murthy <[EMAIL PROTECTED]> > > wrote: > > > > > > > > > > > On Oct 22, 2008, at 2:52 PM, Yih Sun Khoo wrote: > > > > > > > > I like to hear some good ways of passing constants from one job to > the > > > >> next. > > > >> > > > > > > > > Unless I'm missing something: JobConf? A HDFS file? DistributedCache? > > > > > > > > Arun > > > > > > > > > > > > > > > >> These are some ways that I can think of: > > > >> 1) The obvious solution is to carry the constant as part of your > > value > > > >> from > > > >> one job to the next, but that would mean every value would hold that > > > >> constant > > > >> 2) Use the reporter as a hack so that you can set the status > message > > > and > > > >> then get the status message back when u need the constant > > > >> > > > >> Any other ideas? (Also please do not include code) > > > >> > > > > > > > > > > > > > >
