[jira] [Commented] (CALCITE-3590) Support SQL hints for Aggregate.

["Rui Wang (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-3590?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16993782#comment-16993782 ] 

Rui Wang commented on CALCITE-3590:
-----------------------------------

This is also useful for large data processing engine. There is a common case that a hot key exist, which causes troubles on execution engine. Hint on aggregation can be used to provide what are hot keys, and engines can handle those separately.

> Support SQL hints for Aggregate.
> --------------------------------
>
>                 Key: CALCITE-3590
>                 URL: https://issues.apache.org/jira/browse/CALCITE-3590
>             Project: Calcite
>          Issue Type: Sub-task
>          Components: core
>    Affects Versions: 1.21.0
>            Reporter: Shuo Cheng
>            Priority: Major
>             Fix For: 1.22.0
>
>
> Currently in CALCITE-482, hints are only supported for Project, Join and TableScan. It's also necessary to support hints for Aggregate so as to enable fine grained Aggregate configuration, e.g., two-stage-aggregation.
> SELECT /*+ TWO_STAGE_AGG(true) */ 
>  dep_id,
>  grade, 
>  avg(annual_salary),
>  min(annual_salary),
>  max(annual_salary)
>  FROM T
>  GROUP BY dep_id, grade;



--
This message was sent by Atlassian Jira
(v8.3.4#803005)