[ https://issues.apache.org/jira/browse/HIVE-19192?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Rajkumar Singh updated HIVE-19192: ---------------------------------- Attachment: query-with-100-union.q query-with-50-union.q query-with-200-union.q > HiveServer2 query compilation : query compilation time increases sql has > multiple unions > ----------------------------------------------------------------------------------------- > > Key: HIVE-19192 > URL: https://issues.apache.org/jira/browse/HIVE-19192 > Project: Hive > Issue Type: Improvement > Components: Hive, HiveServer2 > Affects Versions: 1.2.1, 2.1.0 > Environment: Hive-1.2.1 > Hive-2.1.0 > > Reporter: Rajkumar Singh > Priority: Major > Attachments: query-with-100-union.q, query-with-200-union.q, > query-with-50-union.q > > > query compilation time suffer a lot if SQL has many unions, here is the > simple reproduce of the problem. PFA attached query with 50,100 and 200 > unions(forgive me for this bad SQL). when run explain against hiveserver2 I > can see the compilation time increase many folds. > {code} > query-with-50-union.q > 1,671 rows selected (10.662 seconds) > query-with-100-union.q > 3,321 rows selected (101.709 seconds) > query-with-200-union.q > 6,588 rows selected (1074.487 seconds) > {code} > Running such SQL against hiveserver2 can starve other SQL to run into single > threaded compilation stage. -- This message was sent by Atlassian JIRA (v7.6.3#76005)