Hi, Team   I have a problem when querying select count(*) from table atau select distinct field from table atau select * from table order by field.   when checked through yarn, then application details. error appears :   2017-10-03 16:22:54,826 INFO [IPC Server handler 12 on 35262] org.apache.hadoop.mapred.TaskAttemptListenerImpl: Progress of TaskAttempt attempt_1506588001647_0368_r_000000_0 is : 0.21282798 2017-10-03 16:22:54,827 FATAL [IPC Server handler 10 on 35262] org.apache.hadoop.mapred.TaskAttemptListenerImpl: Task: attempt_1506588001647_0368_r_000000_0 - exited : org.apache.hadoop.mapreduce.task.reduce.Shuffle$ShuffleError: error in shuffle in fetcher#3 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.hadoop.mapred.YarnChild$2.run(YarnChild.java:164) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1709) at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158) Caused by: java.io.IOException: Exceeded MAX_FAILED_UNIQUE_FETCHES; bailing-out. at org.apache.hadoop.mapreduce.task.reduce.ShuffleSchedulerImpl.checkReducerHealth(ShuffleSchedulerImpl.java:391) at org.apache.hadoop.mapreduce.task.reduce.ShuffleSchedulerImpl.copyFailed(ShuffleSchedulerImpl.java:306) at org.apache.hadoop.mapreduce.task.reduce.Fetcher.openShuffleUrl(Fetcher.java:294) at org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyFromHost(Fetcher.java:335) at org.apache.hadoop.mapreduce.task.reduce.Fetcher.run(Fetcher.java:198)   can be helped on this    Many Thanks ... View more