You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@kylin.apache.org by "ASF GitHub Bot (JIRA)" <ji...@apache.org> on 2019/03/18 05:59:00 UTC
[jira] [Commented] (KYLIN-3883) Kylin supports column count
aggregation
[ https://issues.apache.org/jira/browse/KYLIN-3883?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16794754#comment-16794754 ]
ASF GitHub Bot commented on KYLIN-3883:
---------------------------------------
xbirbird commented on pull request #528: KYLIN-3883 Kylin supports column count aggregation
URL: https://github.com/apache/kylin/pull/528
Kylin目前只支持对常量1进行count聚合预计算，即count(1)，count(col_1)的查询内部全部重写到对count(1)的查询，这样会导致一个问题：当col_1列中存在null值时，count(col_1)的查询结果并不准确。这样就导致Kylin的查询结果和Hive、Spark等不一致。该Patch中，提供了对count(col_1)的支持。
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
users@infra.apache.org
> Kylin supports column count aggregation
> ---------------------------------------
>
> Key: KYLIN-3883
> URL: https://issues.apache.org/jira/browse/KYLIN-3883
> Project: Kylin
> Issue Type: New Feature
> Components: Job Engine
> Affects Versions: all
> Reporter: xiaodongzhang
> Assignee: xiaodongzhang
> Priority: Major
> Fix For: v3.0.0
>
>
> Kylin目前只支持对常量1进行count聚合预计算，即count(1)，count(col_1)的查询内部全部重写到对count(1)的查询，这样会导致一个问题：当col_1列中存在null值时，count(col_1)的查询结果并不准确。这样就导致Kylin的查询结果和Hive、Spark等不一致。该Patch中，提供了对count(col_1)的支持。
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)