[ https://issues.apache.org/jira/browse/HIVE-3773?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Work on HIVE-3773 started by Gang Tim Liu. > Share input scan by unions across multiple queries > -------------------------------------------------- > > Key: HIVE-3773 > URL: https://issues.apache.org/jira/browse/HIVE-3773 > Project: Hive > Issue Type: Improvement > Components: Query Processor > Reporter: Namit Jain > Assignee: Gang Tim Liu > > Consider a query like: > select * from > ( > select key, 1 as value, count(1) from src group by key > union all > select 1 as key, value, count(1) from src group by value > union all > select key, value, count(1) from src group by key, value > ) s; > src is scanned multiple times currently (one per sub-query). > This should be treated like a multi-table insert by the optimizer. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira