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From "Gopal V (JIRA)" <>
Subject [jira] [Created] (HIVE-9645) Constant folding case NULL equality
Date Tue, 10 Feb 2015 22:48:11 GMT
Gopal V created HIVE-9645:

             Summary: Constant folding case NULL equality
                 Key: HIVE-9645
             Project: Hive
          Issue Type: Bug
          Components: Logical Optimizer
    Affects Versions: 1.2.0
            Reporter: Gopal V

Hive logical optimizer does not follow the Null scan codepath when encountering a NULL = 1;

NULL = 1 is not evaluated as false in the constant propogation implementation.

hive> explain select count(1) from store_sales where null=1;
                  alias: store_sales
                  filterExpr: (null = 1) (type: boolean)
                  Statistics: Num rows: 550076554 Data size: 49570324480 Basic stats: COMPLETE
Column stats: COMPLETE
                  Filter Operator
                    predicate: (null = 1) (type: boolean)
                    Statistics: Num rows: 275038277 Data size: 0 Basic stats: PARTIAL Column

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