David Mollitor created HIVE-23194: ------------------------------------- Summary: Use Queue Instead of List for CollectOperator Key: HIVE-23194 URL: https://issues.apache.org/jira/browse/HIVE-23194 Project: Hive Issue Type: Improvement Reporter: David Mollitor Assignee: David Mollitor
https://github.com/apache/hive/blob/d6948a28ab3e34e5116591a60a96bdf031185e47/ql/src/java/org/apache/hadoop/hive/ql/exec/CollectOperator.java#L85-L88 {code:java|title=CollectOperator.java} rowList = new ArrayList<Object>(); ... } else { result.o = rowList.remove(0); result.oi = standardRowInspector; } {code} Removing from the head of an {{ArrayList}} is an expensive operation because it needs to shift all of the elements down in the array for each call. Better to use a {{Queue}} -- This message was sent by Atlassian Jira (v8.3.4#803005)