[jira] [Created] (HIVE-21915) Hive with TEZ UNION ALL and UDTF results in data loss

[Wei Zhang (JIRA)]

Wei Zhang created HIVE-21915:
--------------------------------

             Summary: Hive with TEZ UNION ALL and UDTF results in data loss
                 Key: HIVE-21915
                 URL: https://issues.apache.org/jira/browse/HIVE-21915
             Project: Hive
          Issue Type: Bug
    Affects Versions: 1.2.1
            Reporter: Wei Zhang


The HQL syntax is like this:

CREATE TEMPORARY TABLE tez_union_all_loss_data AS
SELECT xxx, yyy, zzz,1 as tag
FROM ods_1

UNION ALL

SELECT xxx, yyy, zzz, tag
FROM
(
SELECT xxx
,get_json_object(get_json_object(tb,'$.a'),'$.b') AS yyy
,zzz
,2 as tag
FROM ods_2
LATERAL VIEW EXPLODE(some_udf(uuu)) team_number AS tb
) tbl 
;

 

With above HQL, we are expecting that rows with both tag = 2 and tag = 1 
appear. In our case however, all the rows with tag = 1 are lost.

Dig deeper we can find that the generated two maps have identical task tmp 
paths. And that results from when UDTF is present, the FileSinkOperator will be 
processed twice generating the tmp path in GenTezUtils.removeUnionOperators();

 



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