Sekine, You may want to go to the jobtracker web interface and look at the failed task logs for more info.
Mark On Sun, Dec 16, 2012 at 1:36 PM, Sékine Coulibaly <scoulib...@gmail.com> wrote: > Hi there, > > I loaded data from the movielens database into hive, into a u_data table. I > wish I could count the total number of rows in that table. > Although mapreduce task starts, it ends with a Null Pointer Exception. > > I must admit I don't know what to do next, how to investigate this issue. > The standard output is as follows : > > hive> describe u_data; > OK > userid int > movieid int > rating int > unixtime string > Time taken: 3.421 seconds > hive> select count(1) from u_data where userid=1; > Total MapReduce jobs = 1 > Launching Job 1 out of 1 > Number of reduce tasks determined at compile time: 1 > In order to change the average load for a reducer (in bytes): > set hive.exec.reducers.bytes.per.reducer=<number> > In order to limit the maximum number of reducers: > set hive.exec.reducers.max=<number> > In order to set a constant number of reducers: > set mapred.reduce.tasks=<number> > Starting Job = job_201212161709_0002, Tracking URL = > http://localhost.localdomain:50030/jobdetails.jsp?jobid=job_201212161709_0002 > Kill Command = /usr/lib/hadoop/bin/hadoop job > -Dmapred.job.tracker=localhost.localdomain:8021 -kill job_201212161709_0002 > Hadoop job information for Stage-1: number of mappers: 1; number of > reducers: 1 > 2012-12-16 18:07:55,502 Stage-1 map = 0%, reduce = 0% > 2012-12-16 18:08:15,627 Stage-1 map = 100%, reduce = 100% > Ended Job = job_201212161709_0002 with errors > Error during job, obtaining debugging information... > Examining task ID: task_201212161709_0002_m_000002 (and more) from job > job_201212161709_0002 > Exception in thread "Thread-23" java.lang.NullPointerException > at > org.apache.hadoop.hive.shims.Hadoop23Shims.getTaskAttemptLogUrl(Hadoop23Shims.java:44) > at > org.apache.hadoop.hive.ql.exec.JobDebugger$TaskInfoGrabber.getTaskInfos(JobDebugger.java:186) > at > org.apache.hadoop.hive.ql.exec.JobDebugger$TaskInfoGrabber.run(JobDebugger.java:142) > at java.lang.Thread.run(Thread.java:662) > FAILED: Execution Error, return code 2 from > org.apache.hadoop.hive.ql.exec.MapRedTask > MapReduce Jobs Launched: > Job 0: Map: 1 Reduce: 1 HDFS Read: 0 HDFS Write: 0 FAIL > Total MapReduce CPU Time Spent: 0 msec > > Thank you ! > Regards
