大人の事情で古い CDH 5.1.2 を素の設定で使うと Reducer で OOME が出たり出なかったりする。 2016-02-12 00:58:44,134 WARN [main] org.apache.hadoop.mapred.YarnChild: Exception running child : org.apache.hadoop.mapreduce.task.reduce.Shuffle$ShuffleError: error in shuffle in fetcher#1 at org.apache.hadoop.mapreduce.task.reduce.Shuffle.run(Shuffle.java:134) at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:376) at org.apache.h
![象の虫を踏んだ話 - garbagetown](https://cdn-ak-scissors.b.st-hatena.com/image/square/29e2d8f5dbedaeb53da95d76b036a04de3d9e90c/height=288;version=1;width=512/http%3A%2F%2Fcdn-ak.f.st-hatena.com%2Fimages%2Ffotolife%2Fg%2Fgarbagetown%2F20160311%2F20160311203803.png)