运行mapreduce程序时“Java堆空间内存不足错误”
我在运行mapreduce程序时遇到Out Of Memory错误。如果我将260个文件保存在一个文件夹中并将其作为输入提供给mapreduce程序，则显示Java Heap space Out of Memory错误。如果我只提供100个文件作为输入mapreduce，运行正常。那么如何限制mapreduce程序一次只能获取100个文件（~50MB）。 任何人都可以就此问题提出建议……
没有文件：318，块数：1（块大小：128MB），Hadoop在32位系统上运行
My StackTrace: ============== 15/05/05 11:52:47 INFO input.FileInputFormat: Total input paths to process : 318 15/05/05 11:52:47 INFO input.CombineFileInputFormat: DEBUG: Terminated node allocation with : CompletedNodes: 1, size left: 52027734 15/05/05 11:52:47 INFO mapreduce.JobSubmitter: number of splits:1 15/05/05 11:52:47 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_local634564612_0001 15/05/05 11:52:47 WARN conf.Configuration: file:/app/hadoop/tmp/mapred/staging/raghuveer634564612/.staging/job_local634564612_0001/job.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.retry.interval; Ignoring. 15/05/05 11:52:47 WARN conf.Configuration: file:/app/hadoop/tmp/mapred/staging/raghuveer634564612/.staging/job_local634564612_0001/job.xml:an attempt to override final parameter: mapreduce.job. end-notification.max.attempts; Ignoring. 15/05/05 11:52:48 WARN conf.Configuration: file:/var/hadoop/mapreduce/localRunner/raghuveer/job_local634564612_0001/job_local634564612_0001.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.retry.interval; Ignoring. 15/05/05 11:52:48 WARN conf.Configuration: file:/var/hadoop/mapreduce/localRunner/raghuveer/job_local634564612_0001/job_local634564612_0001.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.attempts; Ignoring. 15/05/05 11:52:48 INFO mapreduce.Job: The url to track the job: http://localhost:8080/ 15/05/05 11:52:48 INFO mapreduce.Job: Running job: job_local634564612_0001 15/05/05 11:52:48 INFO mapred.LocalJobRunner: OutputCommitter set in config null 15/05/05 11:52:48 INFO mapred.LocalJobRunner: OutputCommitter is org.apache.hadoop.mapreduce.lib.output.FileOutputCommitter 15/05/05 11:52:48 INFO mapred.LocalJobRunner: Waiting for map tasks 15/05/05 11:52:48 INFO mapred.LocalJobRunner: Starting task: attempt_local634564612_0001_m_000000_0 15/05/05 11:52:48 INFO mapred.Task: Using ResourceCalculatorProcessTree : [ ] 15/05/05 11:52:48 INFO mapred.MapTask: Processing split: Paths:/user/usr/local/upload/20120713T07-45-42.682358000Z_79.150.138.86-1412.c2s_ndttrace:0+78550,/user/usr/local/upload/20120713T07-45-43.356723000Z_151.40.240.66-53426.c2s_ndttrace:0+32768,/user/usr/local/upload/20120713T07-45-43.718556000Z_85.26.235.102-25300.c2s_ndttrace:0+10130,/user/usr/local/upload ..... ..... ..... /20120713T08-33-41.259331000Z_84.122.129.103-61321.c2s_ndttrace:0+19148,/user/usr/local/upload/20120713T08-33-54.972649000Z_86.69.144.214-49599.c2s_ndttrace:0+63014,/user/usr/local/upload/20120713T08-33-56.162340000Z_41.143.91.156-50785.c2s_ndttrace:0+13658,/user/usr/local/upload/20120713T08-33-59.768261000Z_31.187.12.141-50274.c2s_ndttrace:0+126542,/user/usr/local/upload/20120713T08-34-03.950055000Z_78.119.172.109-51495.c2s_ndttrace:0+92676,/user/usr/local/upload/20120713T08-34-08.378534000Z_87.7.113.115-62238.c2s_ndttrace:0+49410,/user/usr/local/upload/20120713T08-34-26.258570000Z_151.13.227.66-33198.c2s_ndttrace:0+2666092 15/05/05 11:52:49 INFO mapreduce.Job: Job job_local634564612_0001 running in uber mode : false 15/05/05 11:52:49 INFO mapreduce.Job: map 0% reduce 0% 15/05/05 11:52:50 INFO mapred.MapTask: Map output collector class = org.apache.hadoop.mapred.MapTask$MapOutputBuffer 15/05/05 11:52:53 INFO mapred.MapTask: (EQUATOR) 0 kvi 78643196(314572784) 15/05/05 11:52:53 INFO mapred.MapTask: mapreduce.task.io.sort.mb: 300 15/05/05 11:52:53 INFO mapred.MapTask: soft limit at 251658240 15/05/05 11:52:53 INFO mapred.MapTask: bufstart = 0; bufvoid = 314572800 15/05/05 11:52:53 INFO mapred.MapTask: kvstart = 78643196; length = 19660800 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (82) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (82) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:54 WARN pcap.PcapReader: Payload start (74) is larger than packet data (68). Returning empty payload. 15/05/05 11:52:55 INFO mapred.MapTask: Starting flush of map output 15/05/05 11:52:55 INFO mapred.MapTask: Spilling map output 15/05/05 11:52:55 INFO mapred.MapTask: bufstart = 0; bufend = 105296; bufvoid = 314572800 15/05/05 11:52:55 INFO mapred.MapTask: kvstart = 78643196(314572784); kvend = 78637988(314551952); length = 5209/19660800 15/05/05 11:52:55 INFO mapred.LocalJobRunner: map > map 15/05/05 11:52:55 INFO mapred.MapTask: Finished spill 0 15/05/05 11:52:55 INFO mapred.LocalJobRunner: map task executor complete. 15/05/05 11:52:55 WARN mapred.LocalJobRunner: job_local634564612_0001 java.lang.Exception: java.lang.OutOfMemoryError: Java heap space at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:462) at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:522) Caused by: java.lang.OutOfMemoryError: Java heap space at net.ripe.hadoop.pcap.PcapReader.nextPacket(PcapReader.java:208) at net.ripe.hadoop.pcap.PcapReader.access$0(PcapReader.java:173) at net.ripe.hadoop.pcap.PcapReader$PacketIterator.fetchNext(PcapReader.java:554) at net.ripe.hadoop.pcap.PcapReader$PacketIterator.hasNext(PcapReader.java:559) at net.ripe.hadoop.pcap.io.reader.PcapRecordReader.nextKeyValue(PcapRecordReader.java:57) at net.ripe.hadoop.pcap.io.reader.CombineBinaryRecordReader.nextKeyValue(CombineBinaryRecordReader.java:42) at org.apache.hadoop.mapreduce.lib.input.CombineFileRecordReader.nextKeyValue(CombineFileRecordReader.java:69) at org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.nextKeyValue(MapTask.java:533) at org.apache.hadoop.mapreduce.task.MapContextImpl.nextKeyValue(MapContextImpl.java:80) at org.apache.hadoop.mapreduce.lib.map.WrappedMapper$Context.nextKeyValue(WrappedMapper.java:91) at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144) at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:340) at org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:243) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745) 15/05/05 11:52:56 INFO mapreduce.Job: Job job_local634564612_0001 failed with state FAILED due to: NA 15/05/05 11:52:56 INFO mapreduce.Job: Counters: 25 File System Counters FILE: Number of bytes read=29002348 FILE: Number of bytes written=29450636 FILE: Number of read operations=0 FILE: Number of large read operations=0 FILE: Number of write operations=0 HDFS: Number of bytes read=103142 HDFS: Number of bytes written=0 HDFS: Number of read operations=6 HDFS: Number of large read operations=0 HDFS: Number of write operations=1 Map-Reduce Framework Map input records=1303 Map output records=1303 Map output bytes=105296 Map output materialized bytes=0 Input split bytes=38078 Combine input records=0 Spilled Records=0 Failed Shuffles=0 Merged Map outputs=0 GC time elapsed (ms)=593 CPU time spent (ms)=0 Physical memory (bytes) snapshot=0 Virtual memory (bytes) snapshot=0 Total committed heap usage (bytes)=1745092608 File Input Format Counters Bytes Read=0 步骤1：
在hadoop主目录中找到的.bashrc文件中添加以下行：
export JVM_ARGS="-Xms1024m -Xmx1024m"
这会将java堆内存更改为1024.默认值为128.如果您正在运行终端hadoop作业，请以hadoop用户身份执行此操作：
source ~/.bashrc
如果仍然出现错误，请尝试第2步。
第2步：
在hadoop-env.sh文件中添加以下行：
export HADOOP_CLIENT_OPTS="-Xmx1024m $HADOOP_CLIENT_OPTS"
如果仍然没有运气，请尝试第3步。
第3步：
在mapred-site.xml文件中添加此属性：
mapred.child.java.opts -Xmx1024m
所有这些步骤都会增加默认的Java堆内存。