EdisonWang created SPARK-29343: ---------------------------------- Summary: Eliminate sorts without limit in the subquery of Join/Aggregation Key: SPARK-29343 URL: https://issues.apache.org/jira/browse/SPARK-29343 Project: Spark Issue Type: Improvement Components: SQL Affects Versions: 3.0.0 Reporter: EdisonWang
The {{Sort}} without {{Limit}} operator in {{Join/GroupBy}} subquery is useless. For example, {{select count(1) from (select a from test1 order by a)}} is equal to {{select count(1) from (select a from test1)}}. 'select * from (select a from test1 order by a) t1 join (select b from test2) t2 on t1.a = t2.b' is equal to {{select * from (select a from test1) t1 join (select b from test2) t2 on t1.a = t2.b}}. Remove useless {{Sort}} operator can import performance. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org