[jira] [Updated] (CALCITE-7604) Add rule to pull up GROUP BY above JOIN

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CALCITE-7604?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ASF GitHub Bot updated CALCITE-7604:
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    Labels: pull-request-available  (was: )

> Add rule to pull up GROUP BY above JOIN
> ---------------------------------------
>
>                 Key: CALCITE-7604
>                 URL: https://issues.apache.org/jira/browse/CALCITE-7604
>             Project: Calcite
>          Issue Type: New Feature
>          Components: core
>            Reporter: Stamatis Zampetakis
>            Assignee: Stamatis Zampetakis
>            Priority: Major
>              Labels: pull-request-available
>
> Implement a new rule to pull up a GROUP BY above a JOIN when possible. The major benefit of the group-by pull up transformation is that the join may reduce the number of input rows to the group-by, if the join is selective.
> The idea of pulling the aggregation above a join is rather old and the following research papers are among the first that describe the individual transformations to a greater extend:
>  # Yan & Larson (1995) "Interchanging the order of grouping and join" Technical Report 
>  # Yan & Larson (1995) "Eager Aggregation and Lazy Aggregation", VLDB
> Below a simple query demonstrating the group by pull up transformation using SQL syntax.
> +Before+
> {code:sql}
> SELECT s.sales
> FROM (SELECT ss_sold_date_sk, SUM(ss_sales_price) AS sales
>       FROM store_sales
>       GROUP BY ss_sold_date_sk) s
> JOIN date_dim d
>   ON s.ss_sold_date_sk = d.d_date_sk
> WHERE d.d_year = 2000;
> {code}
> +After+
> {code:sql}
> SELECT SUM(ss_sales_price) AS sales
> FROM store_sales s
> JOIN date_dim d
>   ON s.ss_sold_date_sk = d.d_date_sk
> WHERE d.d_year = 2000
> GROUP BY s.ss_sold_date_sk;
> {code}
> More examples can be found in the respective papers.
> The first version of the rule aims to cover the simplest form of group-by pull up described under "Interchanging the order of grouping and join". The more advanced "lazy" variants can be implemented in follow-ups.



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