Revision 1301310

HIVE-2778 [jira] Fail on table sampling
(Navis Ryu via Carl Steinbach)

Summary:
HIVE-2778 fix NPE on table sampling

Trying table sampling on any non-empty table throws NPE. This does not occur by
test on mini-MR.  <div class="preformatted panel" style="border-width:
1px;"><div class="preformattedContent panelContent"> <pre>select count(*) from
emp tablesample (0.1 percent);      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>
java.lang.NullPointerException 	at
org.apache.hadoop.hive.ql.io.CombineHiveInputFormat.sampleSplits(CombineHiveInputFormat.java:450)
	at
org.apache.hadoop.hive.ql.io.CombineHiveInputFormat.getSplits(CombineHiveInputFormat.java:403)
	at org.apache.hadoop.mapred.JobClient.writeOldSplits(JobClient.java:971) 	at
org.apache.hadoop.mapred.JobClient.writeSplits(JobClient.java:963) 	at
org.apache.hadoop.mapred.JobClient.access$500(JobClient.java:170) 	at
org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:880) 	at
org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:833) 	at
java.security.AccessController.doPrivileged(Native Method) 	at
javax.security.auth.Subject.doAs(Subject.java:396) 	at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1127)
	at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:833) 	at
org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java:807) 	at
org.apache.hadoop.hive.ql.exec.ExecDriver.execute(ExecDriver.java:432) 	at
org.apache.hadoop.hive.ql.exec.MapRedTask.execute(MapRedTask.java:136) 	at
org.apache.hadoop.hive.ql.exec.Task.executeTask(Task.java:134) 	at
org.apache.hadoop.hive.ql.exec.TaskRunner.runSequential(TaskRunner.java:57) 	at
org.apache.hadoop.hive.ql.Driver.launchTask(Driver.java:1332) 	at
org.apache.hadoop.hive.ql.Driver.execute(Driver.java:1123) 	at
org.apache.hadoop.hive.ql.Driver.run(Driver.java:931) 	at
org.apache.hadoop.hive.cli.CliDriver.processLocalCmd(CliDriver.java:255) 	at
org.apache.hadoop.hive.cli.CliDriver.processCmd(CliDriver.java:212) 	at
org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:403) 	at
org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:671) 	at
org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:554) 	at
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 	at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597) 	at
org.apache.hadoop.util.RunJar.main(RunJar.java:186) Job Submission failed with
exception 'java.lang.NullPointerException(null)' FAILED: Execution Error, return
code 1 from org.apache.hadoop.hive.ql.exec.MapRedTask  </pre> </div></div>

Test Plan: EMPTY

Reviewers: JIRA, cwsteinbach

Reviewed By: cwsteinbach

Differential Revision: https://reviews.facebook.net/D1593