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From "Gopal V (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-21368) Vectorization: Unnecessary Decimal64 -> HiveDecimal conversion
Date Fri, 01 Mar 2019 18:10:00 GMT

    [ https://issues.apache.org/jira/browse/HIVE-21368?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16781948#comment-16781948
] 

Gopal V commented on HIVE-21368:
--------------------------------

The real impact of this is downstream of the join operator - when we sum(7,2) -> 17,2,
we should be able to use VectorUDAFSumDecimal64

> Vectorization: Unnecessary Decimal64 -> HiveDecimal conversion
> --------------------------------------------------------------
>
>                 Key: HIVE-21368
>                 URL: https://issues.apache.org/jira/browse/HIVE-21368
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Gopal V
>            Priority: Major
>
> Joins projecting Decimal64 have a suspicious cast in the inner loop
> {code}
> ConvertDecimal64ToDecimal(col 14:decimal(7,2)/DECIMAL_64) -> 24:decimal(7,2)'
> {code}
> {code}
> create temporary table foo(x int , y decimal(7,2));
> create temporary table bar(x int , y decimal(7,2));
> set hive.explain.user=false;
> explain vectorization detail select sum(foo.y) from foo, bar where foo.x = bar.x;
> {code}
> {code}
> '                      Map Join Operator'
> '                        condition map:'
> '                             Inner Join 0 to 1'
> '                        keys:'
> '                          0 _col0 (type: int)'
> '                          1 _col0 (type: int)'
> '                        Map Join Vectorization:'
> '                            bigTableKeyColumnNums: [0]'
> '                            bigTableRetainedColumnNums: [3]'
> '                            bigTableValueColumnNums: [3]'
> '                            bigTableValueExpressions: ConvertDecimal64ToDecimal(col
1:decimal(7,2)/DECIMAL_64) -> 3:decimal(7,2)'
> '                            className: VectorMapJoinInnerBigOnlyLongOperator'
> '                            native: true'
> '                            nativeConditionsMet: hive.mapjoin.optimized.hashtable IS
true, hive.vectorized.execution.mapjoin.native.enabled IS true, hive.execution.engine tez
IN [tez, spark] IS true, One MapJoin Condition IS true, No nullsafe IS true, Small table vectorizes
IS true, Fast Hash Table and No Hybrid Hash Join IS true'
> '                            projectedOutputColumnNums: [3]'
> {code}



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