[jira] [Closed] (IMPALA-5936) Difference between the % Operator and Mod function with large decimal values

["Zoltán Borók-Nagy (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-5936?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Zoltán Borók-Nagy closed IMPALA-5936.
-------------------------------------
       Resolution: Fixed
    Fix Version/s: Impala 2.11.0

Fixed in https://github.com/cloudera/Impala/commit/1fedba309a32a5a6b1a1f4b9c077cc989336551c

> Difference between the % Operator and Mod function with large decimal values
> ----------------------------------------------------------------------------
>
>                 Key: IMPALA-5936
>                 URL: https://issues.apache.org/jira/browse/IMPALA-5936
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Frontend
>            Reporter: Jason Phelps
>            Assignee: Zoltán Borók-Nagy
>             Fix For: Impala 2.11.0
>
>
> It looks like the '%' operator breaks in the following scenario:
> decimal(18,0) + Any value greater than INT (2147483647)  
> As far as I can tell, `%` will typically use the proper mod function transparently, but instead of using/casting as BIGINT, it will use INT, and then overflow. If I directly cast as BIGINT, it will work as expected.
> | num         | num % 3 | mod(num, 3) |
> | 42607032167 | -2      | 2           |
> | 42606774111 | -1      | 0           |
> | 42363009429 | -1      | 0           |
> | 42603003271 | 0       | 1           |
> | 42606961501 | 0       | 1           |
> | 42608445511 | 0       | 1           |
> | 42607368197 | -2      | 2           |
> | 42606319059 | -1      | 0           |
> | 42602678339 | -2      | 2           |
> | 42260146355 | -2      | 2           |
> If the number is used directly (i.e. not using a column), it works as expected:
> | 42607032167 % 3 | mod(42607032167, 3) |
> | 2               | 2                   |
> According to the documentation, these should be equivalent
> {quote}mod(numeric_type a, same_type b)
> Purpose: Returns the modulus of a number. Equivalent to the % arithmetic operator. Works with any size integer type, any size floating-point type, and DECIMAL with any precision and scale.
> {quote} 



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