[HIVE-790] race condition related to ScriptOperator + UnionOperator

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.4.0
• Component/s: Query Processor
• Hadoop Flags: Reviewed
• Assignee: Ning Zhang
• Reporter: Zheng Shao
• Created: 25/Aug/09 00:56
• Updated: 17/Dec/11 00:07
• Resolved: 01/Sep/09 21:36

Description

ScriptOperator uses a second thread to output the rows to the children operators. In a corner case which contains a union, 2 threads might be outputting data into the same operator hierarchy and caused race conditions.

CREATE TABLE tablea (cola STRING);
SELECT *
FROM (
    SELECT TRANSFORM(cola)
    USING 'cat'
    AS cola
    FROM tablea
  UNION ALL
    SELECT cola as cola
    FROM tablea
) a;