The (http://blog.csdn.net/yfkiss/article/details/7752180) in the hive document does not state a type called void
However, the void type exists, and accessing a table with the void type will cause some problems!
As follows:
> Select * From;
OK
Null null
1 null
> Create Table Test
>
> Select a. Key, A. value,
Null as TMP
> From;
.....
> DESC test;
OK
Key int
Value string
TMP void
> Select * from test;
OK
Failed with exception java. Io. ioexception: Java. Lang. runtimeexception: Internal error: No lazyobject for void
Time taken: 0.075 seconds
If the query does not involve the void field, worse, it will cause a running error, and more difficult to find the error!
> Select key from test;
Total mapreduce jobs = 1
Launching job 1 out of 1
Number of reduce tasks is set to 0 since there's no reduce Operator
Starting job = job_201301101933_0010, tracking url = http: // localhost: 50030/jobdetails. jsp? Jobid = job_201301101933_0010
Kill command =/home/work/hadoop/hadoop-1.0.3/libexec/../bin/hadoop job-dmapred. Job. Tracker = localhost: 9001-kill job_201301101933_0010
Hadoop job information for stage-1: Number of mappers: 1; number of concurrent CERs: 0
18:53:38, 497 stage-1 Map = 0%, reduce = 0%
18:54:08, 651 stage-1 Map = 100%, reduce = 100%
Ended job = job_201301101933_0010 with errors
Error during job, obtaining debugging information...
Examining task id: task_201301101933_0010_m_000002 (and more) from job job_201301101933_0010
Exception in thread "thread-73" Java. Lang. runtimeexception: Error while reading from task log URL
At org.apache.hadoop.hive.ql.exe C. errors. tasklogprocessor. geterrors (tasklogprocessor. Java: 130)
At org.apache.hadoop.hive.ql.exe C. jobdebugger. showjobfaildebuginfo (jobdebugger. Java: 211)
At org.apache.hadoop.hive.ql.exe C. jobdebugger. Run (jobdebugger. Java: 81)
At java. Lang. thread. Run (thread. Java: 679)
Caused by: Java. Io. ioexception: server returned HTTP response code: 400 for URL: http: // Ubuntu: 50060/tasklog? Taskid = attempt_201301101933_0010_m_000000_1 & START =-8193
At sun.net. www. Protocol. http. httpurlconnection. getinputstream (httpurlconnection. Java: 1403)
At java.net. url. openstream (URL. Java: 1029)
At org.apache.hadoop.hive.ql.exe C. errors. tasklogprocessor. geterrors (tasklogprocessor. Java: 120)
... 3 more
Failed: execution error, return code 2 from org.apache.hadoop.hive.ql.exe C. mapredtask
Mapreduce Jobs launched:
Job 0: Map: 1 HDFS read: 0 HDFS write: 0 fail
Total mapreduce CPU time spent: 0 msec