Reducers fail with OutOfMemoryError while copying Map outputs -------------------------------------------------------------
Key: HADOOP-6357 URL: https://issues.apache.org/jira/browse/HADOOP-6357 Project: Hadoop Common Issue Type: Bug Affects Versions: 0.20.0 Reporter: Chandra Prakash Bhagtani Reducers fail while copying Map outputs with following exception java.lang.OutOfMemoryError: Java heap space at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$MapOutputCopier.shuffleInMemory(ReduceTask.java:1539) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$MapOutputCopier.getMapOutput(ReduceTask.java:1432) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$MapOutputCopier.copyOutput(ReduceTask.java:1285) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$MapOutputCopier.run(ReduceTask.java:1216) ,Error: Reducer's memory usage keeps on increasing and ultimately exceeds -Xmx value I even tried with -Xmx6.5g to each reducer but it's still failing While looking into the reducer logs, I found that reducers were doing shuffleInMemory every time, rather than doing shuffleOnDisk -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.