One more little question, why Hadoop streaming is designed in this way to use 2 different options to do the same thing (i.e. control the reduce number)? What's the point here? Thanks
--- On Fri, 7/18/08, Arun C Murthy <[EMAIL PROTECTED]> wrote: From: Arun C Murthy <[EMAIL PROTECTED]> Subject: Re: [Streaming]What is the difference between streaming options: -file and -CacheFile ? To: core-user@hadoop.apache.org, "Steve Gao" <[EMAIL PROTECTED]> Date: Friday, July 18, 2008, 8:27 PM On Jul 18, 2008, at 4:53 PM, Steve Gao wrote: > Hi All, > I am using Hadoop Streaming. I am confused by streaming > options: -file and -CacheFile. Seems that they mean the same thing, > right? > The difference is that -file will 'ship' your file (local file) to the cluster, while -cachefile assumes that it is already present on HDFS at the given path. > Another misleading options are : -NumReduceTasks and -jobconf > mapred.reduce.tasks. Both are used to control (or give hit to) the > number of reducers. > Yes, they are both equivalent. hth, Arun