[ https://issues.apache.org/jira/browse/HIVE-19283?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16450041#comment-16450041 ]
Gopal V commented on HIVE-19283: -------------------------------- This was fixed sometime during hive-3.x https://github.com/apache/hive/blob/master/ql/src/test/results/clientpositive/tez/multi_count_distinct.q.out > Select count(distinct()) a couple of times stuck in last reducer > ---------------------------------------------------------------- > > Key: HIVE-19283 > URL: https://issues.apache.org/jira/browse/HIVE-19283 > Project: Hive > Issue Type: Improvement > Components: CBO, Logical Optimizer > Affects Versions: 2.1.1 > Reporter: Goun Na > Assignee: Ashutosh Chauhan > Priority: Major > > Distinct count query performance is significantly improved due to > HIVE-10568. > {code:java} > select count(distinct elevenst_id) > from 11st.log_table > where part_dt between '20180101' and '20180131'{code} > > However, some queries with several distinct counts are still slow. It starts > with multiple mappers, but stuck in the last one reducer. > {code:java} > select > count(distinct elevenst_id) > , count(distinct member_id) > , count(distinct user_id) > , count(distinct action_id) > , count(distinct other_id) > from 11st.log_table > where part_dt between '20180101' and '20180131'{code} > -- This message was sent by Atlassian JIRA (v7.6.3#76005)