[
https://issues.apache.org/jira/browse/KYLIN-2620?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16743572#comment-16743572
]
Shaofeng SHI commented on KYLIN-2620:
-------------------------------------
I will check it.
> Check for "ORDER BY LIMIT" clause when rewrite SUM query as TOPN
> ----------------------------------------------------------------
>
> Key: KYLIN-2620
> URL: https://issues.apache.org/jira/browse/KYLIN-2620
> Project: Kylin
> Issue Type: Bug
> Components: Measure - TopN
> Reporter: Lin Tingmao
> Assignee: Shaofeng SHI
> Priority: Major
>
> When running the following query
> select sum(measure) from table group by col_id
> if there exists TOPN(measure, group by col_id) measure,
> TopNMeasureType.isTopNCompatibleSum() will pass, so the SUM is rewritten
> to TOPN. This confuses the user since they may expect a accurate result for
> every distinct value of group by column(s).
> Kylin should check if "ORDER BY col_id LIMIT topncapacity" is present in the
> query to determine whether to rewrite.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
