Earning Points. Starwood's Preferred Guest program is fairly straightforward: the more nights you spend at participating hotels, the faster you'll earn a free night.
As seen in the EXECUTING phase, the map will write (using Mapper.Context.write()) its output into a circular in-memory buffer (MapTask.MapOutputBuffer). The size of this buffer is fixed and determined by the configuration parameter mapreduce.task.io.sort.mb (default: 100MB).
Initially, the data for a MapReduce task is stored in input files, and input files typically reside in HDFS. Although these files format is arbitrary, line-based log files and binary format can be used. Using InputFormat we define how these input files are split and read. The InputFormat class is one of the fundamental classes in the Hadoop MapReduce framework which provides the following functionality: