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Posted to issues@calcite.apache.org by "LeoWangLZ (JIRA)" <ji...@apache.org> on 2018/06/15 06:27:00 UTC

[jira] [Updated] (CALCITE-2204) Volcano Planner may not choose the cheapest cost plan

     [ https://issues.apache.org/jira/browse/CALCITE-2204?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

LeoWangLZ updated CALCITE-2204:
-------------------------------
    Description: Volcano Planner will propagate the cost improvement to parents that one of the inputs has the best plan. But it not propagate to all parents firstly, it propagate one parent and go to the parents of parent. In the way, if one parent may propagate to other parent on the same level, and the cost maybe less than others, but when propagate the parent again, it will not propagate because the cost is already calculated, and it's can't be less then the cost of the self.  (was: Volcano Planner will propagate the cost improvement to parents that one of the inputs has the best plan. But it not propagate to all parents firstly, it propagate one parent and go to the parent s of parent. In the way, if one parent may propagate to other parent on the same level, and the cost maybe less than others, but when propagate the parent again, it will not propagate because the cost is already calculated, and it's can't be less then the cost of the self.)

> Volcano Planner may not choose the cheapest cost plan 
> ------------------------------------------------------
>
>                 Key: CALCITE-2204
>                 URL: https://issues.apache.org/jira/browse/CALCITE-2204
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: LeoWangLZ
>            Assignee: Julian Hyde
>            Priority: Major
>
> Volcano Planner will propagate the cost improvement to parents that one of the inputs has the best plan. But it not propagate to all parents firstly, it propagate one parent and go to the parents of parent. In the way, if one parent may propagate to other parent on the same level, and the cost maybe less than others, but when propagate the parent again, it will not propagate because the cost is already calculated, and it's can't be less then the cost of the self.



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