Hadoop test

Hadoop test

The MRUnit unit tests the Mapper and Reducer classes run independently in memory, and the PipelineMapReduceDriver single thread runs.

LocalJobRunner runs on a single thread, and only one Reducer can start conf.set ("mapred.job.tracker," "local"); c onf.set("fs.default.name", "file:////"); FileSystem fs = FileSystem.getLocal(conf);

MiniMRCluster, MiniYarnCluster, MiniDFSCluster Multithreaded