[jira] [Created] (HIVE-3870) SELECT foo, NULL UNION ALL SELECT bar, baz fails

["David Morel (JIRA)" <ji...@apache.org>]

David Morel created HIVE-3870:
---------------------------------

             Summary: SELECT foo, NULL UNION ALL SELECT bar, baz fails
                 Key: HIVE-3870
                 URL: https://issues.apache.org/jira/browse/HIVE-3870
             Project: Hive
          Issue Type: Bug
    Affects Versions: 0.8.1
            Reporter: David Morel


In order to avoid the curse of the last reducer by using a left outer join where most joined rows woudl be NULLs, I rewrote the query as:
{code}

SELECT * FROM (
    SELECT
        A.user_id id,
        B.created
    FROM (
        SELECT DISTINCT user_id
        FROM users
    ) A
    JOIN
        buyhist B
    ON
        A.user_id = B.user_id
        AND B.created >= '2013-01-01'
    UNION ALL
    SELECT
        DISTINCT(user_id) id,
        NULL created
    FROM users
) foo;
{code}

The expection thrown is this:

{code}
2013-01-07 17:00:01,081 WARN org.apache.hadoop.mapred.Child: Error running child
java.lang.RuntimeException: Error in configuring object
	at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:106)
	at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:72)
	at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:130)
	at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:389)
	at org.apache.hadoop.mapred.MapTask.run(MapTask.java:327)
	at org.apache.hadoop.mapred.Child$4.run(Child.java:270)
	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:1232)
	at org.apache.hadoop.mapred.Child.main(Child.java:264)
Caused by: java.lang.reflect.InvocationTargetException
	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.ReflectionUtils.setJobConf(ReflectionUtils.java:103)
	... 9 more
Caused by: java.lang.RuntimeException: Error in configuring object
	at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:106)
	at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:72)
	at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:130)
	at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:34)
	... 14 more
Caused by: java.lang.reflect.InvocationTargetException
	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.ReflectionUtils.setJobConf(ReflectionUtils.java:103)
	... 17 more
Caused by: java.lang.RuntimeException: Map operator initialization failed
	at org.apache.hadoop.hive.ql.exec.ExecMapper.configure(ExecMapper.java:121)
	... 22 more
Caused by: java.lang.NullPointerException
	at org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector.toString(StructObjectInspector.java:60)
	at java.lang.String.valueOf(String.java:2826)
	at java.lang.StringBuilder.append(StringBuilder.java:115)
	at org.apache.hadoop.hive.ql.exec.UnionOperator.initializeOp(UnionOperator.java:110)
	at org.apache.hadoop.hive.ql.exec.Operator.initialize(Operator.java:357)
	at org.apache.hadoop.hive.ql.exec.MapOperator.initializeOp(MapOperator.java:427)
	at org.apache.hadoop.hive.ql.exec.Operator.initialize(Operator.java:357)
	at org.apache.hadoop.hive.ql.exec.ExecMapper.configure(ExecMapper.java:98)
	... 22 more
{code}

The "org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector.toString(StructObjectInspector.java:60)" caught my attention, so I replaced NULL by an empty string:

{code}
    ...
    UNION ALL
    SELECT
        DISTINCT(user_id) id,
        '' created
{code}

Shouldn't the query parser accept the form using NULL, or at least output a message before the job is sent to the jobtracker?

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