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Posted to issues@calcite.apache.org by "Haisheng Yuan (Jira)" <ji...@apache.org> on 2019/11/06 19:22:00 UTC

[jira] [Updated] (CALCITE-790) Remove relational expressions that reference themselves

     [ https://issues.apache.org/jira/browse/CALCITE-790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Haisheng Yuan updated CALCITE-790:
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    Attachment: image-2019-11-06-11-21-08-004.png

> Remove relational expressions that reference themselves
> -------------------------------------------------------
>
>                 Key: CALCITE-790
>                 URL: https://issues.apache.org/jira/browse/CALCITE-790
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Julian Hyde
>            Assignee: Julian Hyde
>            Priority: Major
>
> Sometimes when two equivalence sets are merged (i.e. discovered to be equivalent) relational expressions in the sets end up referencing themselves. These are impossible to implement, cause a lot of useless rules to fire, and may cause stats calculations to go into a loop.
> We should look for cyclic expressions after merging sets and remove them.



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