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Posted to issues@calcite.apache.org by "Julian Hyde (Jira)" <ji...@apache.org> on 2020/11/13 21:10:00 UTC

[jira] [Comment Edited] (CALCITE-4400) A tool method explain Calc operator

    [ https://issues.apache.org/jira/browse/CALCITE-4400?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17231829#comment-17231829 ] 

Julian Hyde edited comment on CALCITE-4400 at 11/13/20, 9:09 PM:
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In JIRA, use two curly braces around items to convert them to monospace. Backtick is for Github (and Github-inspired markdown).

I agree that this would be useful. Maybe it could be a utility that converts a {{Calc}} into either a {{Project}} or a {{Filter}} followed by a {{Project}}. The utility should take a {{RelBuilder}} as an argument (so that it can use project and filter factories). Explain could call this expand method before printing the {{RelNode}} tree.


was (Author: julianhyde):
In JIRA, use two curly braces around items to convert them to monospace. Backtick is for Github (and Github-inspired markdown).

I agree that this would be useful. Maybe it could be a utility that converts a {{Calc}} into either a {{Project}} or a {{Filter}} followed by a {{Project}}. The utility should take a {{RelBuilder}} as an argument (so that it can use project and filter factories). Explain could call this expand method before printing the RelNode tree.

> A tool method explain Calc operator
> -----------------------------------
>
>                 Key: CALCITE-4400
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4400
>             Project: Calcite
>          Issue Type: Wish
>            Reporter: xzh_dz
>            Priority: Major
>
> `Calc` is an operator combining `Project` and `Filter`. In a project development, `Calc` operator is usually used to simplify the operator of `Project` and `Filter`, and facilitate the optimization of relational algebra. Usually, `Calc` operator is needed to process `Project` and `Filter` information.Explain Calc operator is often needed in materialized view recognition.A tool  is needed to explain Calc to get `Project` (RexNodes) and `Filter` (RexNode). In relation algebra optimization, it will be very convenient to process `Calc` operator.



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