我正在写一个hadoop作业,它处理许多文件并从每个文件创建多个文件。我正在使用“MultipleOutputs”来编写它们。它适用于较小数量的文件,但我得到大量文件的以下错误。 MultipleOutputs.write(key,value,outputPath)引发异常; 我曾尝试增加ulimit和-Xmx但无济于事。Hadoop - MultipleOutputs.write - OutofMemory - Java堆空间
2013-01-15 13:44:05,154 FATAL org.apache.hadoop.mapred.Child: Error running child : java.lang.OutOfMemoryError: Java heap space
at org.apache.hadoop.hdfs.DFSOutputStream$Packet.<init>(DFSOutputStream.java:201)
at org.apache.hadoop.hdfs.DFSOutputStream.writeChunk(DFSOutputStream.java:1423)
at org.apache.hadoop.fs.FSOutputSummer.writeChecksumChunk(FSOutputSummer.java:161)
at org.apache.hadoop.fs.FSOutputSummer.flushBuffer(FSOutputSummer.java:136)
at org.apache.hadoop.fs.FSOutputSummer.flushBuffer(FSOutputSummer.java:125)
at org.apache.hadoop.fs.FSOutputSummer.write1(FSOutputSummer.java:116)
at org.apache.hadoop.fs.FSOutputSummer.write(FSOutputSummer.java:90)
at org.apache.hadoop.fs.FSDataOutputStream$PositionCache.write(FSDataOutputStream.java:54)
at java.io.DataOutputStream.write(DataOutputStream.java:90)
at org.apache.hadoop.mapreduce.lib.output.TextOutputFormat$LineRecordWriter. writeObject(TextOutputFormat.java:78)
at org.apache.hadoop.mapreduce.lib.output.TextOutputFormat$LineRecordWriter. write(TextOutputFormat.java:99)
**at org.apache.hadoop.mapreduce.lib.output.MultipleOutputs.write(MultipleOutputs.java:386)
at com.demoapp.collector.MPReducer.reduce(MPReducer.java:298)
at com.demoapp.collector.MPReducer.reduce(MPReducer.java:28)**
at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:164)
at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:595)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:433)
at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1332)
at org.apache.hadoop.mapred.Child.main(Child.java:262)
任何想法?
我试图使用来设置属性 - 配置CONF = job.getConfiguration(); conf.set(“dfs.datanode.max.xcievers”,“4096”);并且执行了这项工作,但没有任何区别。 – Harpreet
@Harpreet这是一个datanode属性,您需要将它放在hdfs-site.xml中并重新启动群集才能生效。 –