小编给大家分享一下hive join空指针异常的示例分析，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
2015-07-28 10:03:21,557 Stage-2 map = 100%, reduce = 0% Ended Job = job_1437720498561_1035 with errors Error during job, obtaining debugging information... Examining task ID: task_1437720498561_1035_m_000000 (and more) from job job_1437720498561_1035 Task with the most failures(4): ----- Task ID: task_1437720498561_1035_m_000000 URL: http://0.0.0.0:8088/taskdetails.jsp?jobid=job_1437720498561_1035&tipid=task_1437720498561_1035_m_000000 ----- Diagnostic Messages for this Task: Error: java.lang.RuntimeException: java.lang.NullPointerException at org.apache.hadoop.hive.ql.exec.mr.ExecMapper.map(ExecMapper.java:172) at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:54) at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:453) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343) at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:163) 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:1657) at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158) Caused by: java.lang.NullPointerException at org.apache.hadoop.hive.ql.exec.MapJoinoperator.loadHashTable(MapJoinoperator.java:286) at org.apache.hadoop.hive.ql.exec.MapJoinoperator.cleanUpInputFileChangedOp(MapJoinoperator.java:313) at org.apache.hadoop.hive.ql.exec.Operator.cleanUpInputFileChanged(Operator.java:1069) at org.apache.hadoop.hive.ql.exec.Operator.cleanUpInputFileChanged(Operator.java:1073) at org.apache.hadoop.hive.ql.exec.Operator.cleanUpInputFileChanged(Operator.java:1073) at org.apache.hadoop.hive.ql.exec.MapOperator.process(MapOperator.java:501) at org.apache.hadoop.hive.ql.exec.mr.ExecMapper.map(ExecMapper.java:163) ... 8 more Failed: Execution Error, return code 2 from org.apache.hadoop.hive.ql.exec.mr.MapRedTask
hive join 操作时若发生NullPointerException，请执行 set hive.auto.convert.join=false;
如设置hive.auto.convert.join的值为true，hive将在表的大小符合设置时自动使用MapJoin
以上是“hive join空指针异常的示例分析”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注编程之家行业资讯频道！
