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https://issues.apache.org/jira/browse/DRILL-1044?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jacques Nadeau resolved DRILL-1044.
-----------------------------------
Resolution: Fixed
> 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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