[FLINK-8739] Optimize runtime support for distinct filter

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.8.0
• Component/s: Table SQL / API
• Labels: pull-request-available
• Assignee: Dian Fu
• Reporter: Rong Rong
• Created: 21/Feb/18 22:07
• Updated: 19/Sep/19 19:18
• Resolved: 18/Jan/19 12:50

Description

Possible optimizaitons:
1. Decouple distinct map and actual accumulator so that they can separately be created in codegen.
2. Reuse same distinct accumulator for filtering, e.g. `SELECT COUNT(DISTINCT(a)), SUM(DISTINCT(a))` should reuse the same distinct map.

Issue Links

• links to: GitHub Pull Request #7286