[HIVE-20331] Query with union all, lateral view and Join fails with "cannot find parent in the child operator"

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.1.1
• Fix Version/s: 4.0.0-alpha-1
• Component/s: Physical Optimizer
• Assignee: Aihua Xu
• Reporter: Aihua Xu
• Created: 07/Aug/18 17:29
• Updated: 17/Nov/22 08:54
• Resolved: 16/Aug/18 18:25

Description

The following query with Union, Lateral view and Join will fail during execution with the exception below.

create table t1(col1 int);
SELECT 1 AS `col1`
FROM t1
UNION ALL
  SELECT 2 AS `col1`
  FROM
    (SELECT col1
     FROM t1
    ) x1
    JOIN
      (SELECT col1
      FROM
        (SELECT 
          Row_Number() over (PARTITION BY col1 ORDER BY col1) AS `col1`
        FROM t1
        ) x2 lateral VIEW explode(map(10,1))`mapObj` AS `col2`, `col3`
      ) `expdObj`      

Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: Hive internal error: cannot find parent in the child operator!
        at org.apache.hadoop.hive.ql.exec.Operator.initialize(Operator.java:362) ~[hive-exec-4.0.0-SNAPSHOT.jar:4.0.0-SNAPSHOT]
        at org.apache.hadoop.hive.ql.exec.MapOperator.initializeMapOperator(MapOperator.java:509) ~[hive-exec-4.0.0-SNAPSHOT.jar:4.0.0-SNAPSHOT]
        at org.apache.hadoop.hive.ql.exec.mr.ExecMapper.configure(ExecMapper.java:116) ~[hive-exec-4.0.0-SNAPSHOT.jar:4.0.0-SNAPSHOT]

After debugging, seems we have issues in GenMRFileSink1 class in which we are setting incorrect aliasToWork to the MapWork.