[jira] [Commented] (CALCITE-2509) RexSimplify: withParanoid(true).verify takes exponential time as number of variables grows

["Julian Hyde (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-2509?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16597699#comment-16597699 ] 

Julian Hyde commented on CALCITE-2509:
--------------------------------------

Not a huge problem considering that this functionality is intended for testing.

> RexSimplify: withParanoid(true).verify takes exponential time as number of variables grows
> ------------------------------------------------------------------------------------------
>
>                 Key: CALCITE-2509
>                 URL: https://issues.apache.org/jira/browse/CALCITE-2509
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 1.17.0
>            Reporter: Vladimir Sitnikov
>            Assignee: Julian Hyde
>            Priority: Major
>
> The most trivial case is {{coalesce(v1, v2, v3,...)}}
> For instance, it takes 34 seconds to simplify coalesce with 11 inputs.
> {noformat}
> 1, 2 ms, coalesce(vInt(0))
> 2, 1 ms, coalesce(vInt(0), vInt(1))
> 3, 3 ms, coalesce(vInt(0), vInt(1), vInt(2))
> 4, 13 ms, coalesce(vInt(0), vInt(1), vInt(2), vInt(3))
> 5, 28 ms, coalesce(vInt(0), vInt(1), vInt(2), vInt(3), vInt(4))
> 6, 80 ms, coalesce(vInt(0), vInt(1), vInt(2), vInt(3), vInt(4), vInt(5))
> 7, 184 ms, coalesce(vInt(0), vInt(1), vInt(2), vInt(3), vInt(4), vInt(5), vInt(6))
> 8, 661 ms, coalesce(vInt(0), vInt(1), vInt(2), vInt(3), vInt(4), vInt(5), vInt(6), vInt(7))
> 9, 1872 ms, coalesce(vInt(0), vInt(1), vInt(2), vInt(3), vInt(4), vInt(5), vInt(6), vInt(7), vInt(8))
> 10, 7890 ms, coalesce(vInt(0), vInt(1), vInt(2), vInt(3), vInt(4), vInt(5), vInt(6), vInt(7), vInt(8), vInt(9))
> 11, 33889 ms, coalesce(vInt(0), vInt(1), vInt(2), vInt(3), vInt(4), vInt(5), vInt(6), vInt(7), vInt(8), vInt(9), vIntNotNull(0))
> {noformat}



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