[CALCITE-3159] Distinct can be removed for MIN/MAX/BIT_OR/BIT_AND aggregate functions

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.20.0
• Fix Version/s: 1.21.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Danny Chen
• Reporter: Haisheng Yuan
• Created: 29/Jun/19 23:09
• Updated: 24/Sep/19 10:23
• Resolved: 24/Sep/19 10:23

Description

For the following query:

select a, min(distinct b), bit_or(distinct c) from foo group by a;

Currently Calcite still preserve the distinct for these aggregate functions, but DISTINCT is not meaningful with MIN/MAX and is available for ISO compatibility only. We can safely remove distinct and get more optimization opportunities.

Issue Links

• links to: GitHub Pull Request #1335