我在amazon ec2上启动了两个m1.medium节点来执行我的pig脚本，但看起来它在第一行失败了（甚至在MapReduce启动之前）：raw = LOAD 's3n://uw-cse-344-oregon.aws.amazon.com/btc-2010-chunk-000' USING TextLoader as (line:chararray);
我得到的错误信息：
2015-02-04 02:15:39,804 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - 1 map-reduce job(s) waiting for submission.
2015-02-04 02:15:39,821 [JobControl] INFO org.apache.hadoop.mapred.JobClient - Default number of map tasks: null
2015-02-04 02:15:39,822 [JobControl] INFO org.apache.hadoop.mapred.JobClient - Setting default number of map tasks based on cluster size to : 20
... (omitted)
2015-02-04 02:18:40,955 [main] WARN org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - Ooops! Some job has failed! Specify -stop_on_failure if you want Pig to stop immediately on failure.
2015-02-04 02:18:40,956 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - job job_201502040202_0002 has failed! Stop running all dependent jobs
2015-02-04 02:18:40,956 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - 100% complete
2015-02-04 02:18:40,997 [main] ERROR org.apache.pig.tools.pigstats.SimplePigStats - ERROR 2997: Unable to recreate exception from backed error: Error: Java heap space
2015-02-04 02:18:40,997 [main] ERROR org.apache.pig.tools.pigstats.PigStatsUtil - 1 map reduce job(s) failed!
2015-02-04 02:18:40,997 [main] INFO org.apache.pig.tools.pigstats.SimplePigStats - Script Statistics: HadoopVersion PigVersion UserId StartedAt FinishedAt Features 1.0.3 0.11.1.1-amzn hadoop 2015-02-04 02:15:32 2015-02-04 02:18:40 GROUP_BY
Failed!
Failed Jobs:
JobId Alias Feature Message Outputs
job_201502050202_0002 ngroup,raw,triples,tt GROUP_BY,COMBINER Message: Job failed! Error - # of failed Map Tasks exceeded allowed limit. FailedCount: 1. LastFailedTask: task_201502050202_0002_m_000022
Input(s):
Failed to read data from "s3n://uw-cse-344-oregon.aws.amazon.com/btc-2010-chunk-000"
Output(s):
Counters:
Total records written : 0
Total bytes written : 0
Spillable Memory Manager spill count : 0
Total bags proactively spilled: 0
Total records proactively spilled: 0
我认为代码应该很好，因为我曾经成功地加载过具有相同语法的其他数据，并且指向s3n://uw-cse-344-oregon.aws.amazon.com/btc-2010-chunk-000的链接看起来是有效的。我怀疑这可能与我的一些EC2设置有关，但不确定如何进一步调查或缩小问题范围。有人知道线索吗？
"Java堆空间"错误消息提供了一些线索。您的文件似乎相当大（~2GB）。确保每个任务运行者都有足够的内存来读取数据。
当前通过将我的节点从m1.mediate更改为m3.ligh解决了该问题，感谢@Nat的良好提示，他指出了关于java堆空间的错误消息。我稍后会更新更多详细信息。