[jira] [Assigned] (IMPALA-5159) Inequality constraints can be further optimized

["Tim Armstrong (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-5159?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Tim Armstrong reassigned IMPALA-5159:
-------------------------------------

    Assignee:     (was: Zach Amsden)

> Inequality constraints can be further optimized
> -----------------------------------------------
>
>                 Key: IMPALA-5159
>                 URL: https://issues.apache.org/jira/browse/IMPALA-5159
>             Project: IMPALA
>          Issue Type: Improvement
>            Reporter: Zach Amsden
>            Priority: Minor
>
> As a follow up to IMPALA-5003, we can optimize constraints that include multiple minima or maxima to their greatest lower, or least upper bound.
> Example:
> WHERE t.a > 10 AND t.a >= 5 AND t.b < 50 and t.b <= 50 =>
> t.a > 10 AND t.b < 50
> In cases where it is impossible to satisfy the constraints, we can convert conditions to FALSE.
> Further, for inclusive inequality chains, one can deduce from A <= B, B <= C, C <= A =>
> A = B, A = C
> And from exclusive inequality chains, one can infer a contradiction: 
> A <= B, B < C, C <= A => FALSE
> The last two steps require quite a bit more work.



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