MapReduce job Shuffle 過程的ERROR
阿新 • • 發佈:2019-02-02
1.錯誤描述
error: org.apache.hadoop.mapreduce.task.reduce.Shuffle$ShuffleError: error in shuffle in fetcher#43at 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:167)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1550)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:162)
Caused by: java.lang.OutOfMemoryError: Java heap space
at org.apache.hadoop.io.BoundedByteArrayOutputStream.<init>(BoundedByteArrayOutputStream.java:56)
at org.apache.hadoop.io.BoundedByteArrayOutputStream.<init>(BoundedByteArrayOutputStream.java:46)
at org.apache.hadoop.mapreduce.task.reduce.InMemoryMapOutput.<init>(InMemoryMapOutput.java:63)
at org.apache.hadoop.mapreduce.task.reduce.MergeManagerImpl.unconditionalReserve(MergeManagerImpl.java:297)
at org.apache.hadoop.mapreduce.task.reduce.MergeManagerImpl.reserve(MergeManagerImpl.java:287)
at org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyMapOutput(Fetcher.java:414)
at org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyFromHost(Fetcher.java:343)
at org.apache.hadoop.mapreduce.task.reduce.Fetcher.run(Fetcher.java:166)
2.問題解決
從error的stack資訊可以看出是mapreduce 的job shuffle過程中發生的OOM,map的輸出資料在reduce節點load的過多導致的OOM,所以將reduce的shuffle.input 由預設的0.7 改為0.6,該引數的變化需要根據實際情況確定。 conf.set("mapreduce.reduce.shuffle.input.buffer.percent", "0.6");
3.相關引數
- mapreduce.reduce.shuffle.input.buffer.percent :
mapreduce.reduce.shuffle.memory.limit.percent
:
- mapreduce.reduce.shuffle.merge.percent: