[jira] [Updated] (KYLIN-4762) Optimize join where there is the same shardby partition num on join key

["Xiaoxiang Yu (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/KYLIN-4762?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Xiaoxiang Yu updated KYLIN-4762:
--------------------------------
    Fix Version/s: v4.0.0-beta

> Optimize join where there is the same shardby partition num on join key
> -----------------------------------------------------------------------
>
>                 Key: KYLIN-4762
>                 URL: https://issues.apache.org/jira/browse/KYLIN-4762
>             Project: Kylin
>          Issue Type: Improvement
>          Components: Query Engine
>    Affects Versions: v4.0.0-alpha
>            Reporter: Zhichao  Zhang
>            Assignee: Zhichao  Zhang
>            Priority: Minor
>             Fix For: v4.0.0-beta
>
>         Attachments: shardby_join.png
>
>
> Optimize join by reducing shuffle when there is the same shard by partition number on join key.
> When execute this sql,
> {code:java}
> // code placeholder
> select m.seller_id, m.part_dt, sum(m.price) as s 
> from kylin_sales m 
> left join (
>   select m1.part_dt as pd, count(distinct m1.SELLER_ID) as m1, count(1) as m2  
>   from kylin_sales m1
>   where m1.part_dt = '2012-01-05'
>   group by m1.part_dt 
>   ) j 
>   on m.part_dt = j.pd
>   where m.lstg_format_name = 'FP-GTC' 
>   and m.part_dt = '2012-01-05'
>   group by m.seller_id, m.part_dt limit 100;
> {code}
> the execution plan is shown below:
> !shardby_join.png!
> But the join key part_dt has the same shard by partition number, it can be optimized to reduce shuffle, similar to bucket join.



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