title: errors while running hive queries
body: <p>I am trying to run hive queries but I am getting errors as:</p>
  
  <pre><code>hive&gt; FROM (                                                   
      &gt; FROM t1
      &gt; MAP t1.patient_mrn, t1.encounter_date
      &gt; USING 'retrieve'
      &gt; AS mp1, mp2
      &gt; CLUSTER BY mp1) map_output
      &gt;   INSERT OVERWRITE TABLE t3
      &gt; REDUCE map_output.mp1, map_output.mp2
      &gt; USING 'q1.txt'
      &gt; AS reducef1, reducef2;
  </code></pre>
  
  <p>Total MapReduce jobs = 1</p>
  
  <p>Launching Job 1 out of 1</p>
  
  <p>Number of reduce tasks not specified. Estimated from input data size: 1</p>
  
  <p>In order to change the average load for a reducer (in bytes):
    set hive.exec.reducers.bytes.per.reducer=</p>
  
  <p>In order to limit the maximum number of reducers:
    set hive.exec.reducers.max=</p>
  
  <p>In order to set a constant number of reducers:
    set mapred.reduce.tasks=</p>
  
  <p>Starting Job = job_201112281627_0097, Tracking URL = <a href="http://localhost:50030/jobdetails.jsp?jobid=job_201112281627_0097" rel="nofollow">http://localhost:50030/jobdetails.jsp?jobid=job_201112281627_0097</a></p>
  
  <p>Kill Command = /home/hadoop/hadoop-0.20.2-cdh3u2//bin/hadoop job  -Dmapred.job.tracker=localhost:54311 -kill job_201112281627_0097</p>
  
  <p>2011-12-31 03:10:46,391 Stage-1 map = 0%,  reduce = 0%</p>
  
  <p>2011-12-31 03:11:29,794 Stage-1 map = 100%,  reduce = 100%</p>
  
  <p>Ended Job = job_201112281627_0097 with errors
  FAILED: Execution Error, return code 2 from org.apache.hadoop.hive.ql.exec.MapRedTask
  hive> </p>