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Posted to issues@kylin.apache.org by "Shaofeng SHI (JIRA)" <ji...@apache.org> on 2018/01/28 13:33:00 UTC
[jira] [Commented] (KYLIN-3206) Consider SQL expression aggregation
when applying limit push down
[ https://issues.apache.org/jira/browse/KYLIN-3206?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16342568#comment-16342568 ]
Shaofeng SHI commented on KYLIN-3206:
-------------------------------------
Hi Paul, would you like to contribute a patch to Kylin? Thanks!
> Consider SQL expression aggregation when applying limit push down
> -----------------------------------------------------------------
>
> Key: KYLIN-3206
> URL: https://issues.apache.org/jira/browse/KYLIN-3206
> Project: Kylin
> Issue Type: Bug
> Components: Query Engine
> Affects Versions: v1.6.0, v2.2.0
> Environment: Kylin 1.6.0
> Reporter: Paul Lin
> Assignee: liyang
> Priority: Major
>
> SQLs like "select floor(user_level /10), sum(money) group by floor(user_level /10) limit 10" should not trigger storage limit push down, because the expressions like "floor(user_level /10)" are sort of post aggregations. Otherwise Kylin would do aggregations based on partial records, producing inaccurate results.
>
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