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).
The MapReduce System (also called infrastructure or framework) orchestrates the processing by marshalling the distributed servers, running the various tasks in parallel, managing all communications and data transfers between the various parts of the system, and providing for redundancy and fault tolerance.apReduce allows for distributed processing of the map and reduction operations. Provided that each mapping operation is independent of the others, all maps can be performed in parallel â though in practice this is limited by the number of independent data sources and/or the number of CPUs near each source.