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From "Jacques Nadeau (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DRILL-1044) Optimize logical boolean operator evaluation using fast-success/fast-fail approach.
Date Fri, 20 Jun 2014 20:28:33 GMT

    [ https://issues.apache.org/jira/browse/DRILL-1044?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14039306#comment-14039306

Jacques Nadeau commented on DRILL-1044:

fixed in efa3274 or earlier

> Optimize logical boolean operator evaluation using fast-success/fast-fail approach.
> -----------------------------------------------------------------------------------
>                 Key: DRILL-1044
>                 URL: https://issues.apache.org/jira/browse/DRILL-1044
>             Project: Apache Drill
>          Issue Type: Improvement
>            Reporter: Jinfeng Ni
> With short circuit evaluation supported for boolean and/or operators (DRILL-937), we
could further optimize boolean and/or operators by re-ordering the evaluation sequence and
choose to evaluate the cheapest test first.
> For instance, consider we have the following expression :
> really_slow_test ( ...)  && slower_test ( ...) && fast_test ( ...)
> If we choose to evaluate really_slow_test(() first, we will do such test for every input.
 In contrast, if we choose do fast_test() first, we could skip the evaluation of slower_test()
and really_slow_test(), if some input fails at the fast_test().  That is,  performance would
be better, if we transform the expression into:
> fast_test(..)  && slower_test(...) && really_slow_test (....).
> To add such support, we need do :
> 1.  Change the boolean "and"/"or" so that it takes arbitrary  number of operands. ( Previously,
"and"/"or" is processed as taking two operands) This way, we could compare and sort all the
operands under one single "and"/"or" operator.
> 2. Assign a cost category to different functions/operators, to reflect the rough estimation
of each individual function/operator.  
> 3. Re-order the operands based on the cumulative cost for evaluation.

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