[FLINK-5956] Add retract method into the aggregateFunction

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Implemented
• Fix Version/s: 1.3.0
• Component/s: Table SQL / API
• Assignee: Shaoxuan Wang
• Reporter: Shaoxuan Wang
• Created: 03/Mar/17 09:06
• Updated: 07/Mar/17 18:00
• Resolved: 07/Mar/17 18:00

Description

Retraction method is help for processing updated message. It will also very helpful for window Aggregation. This PR will first add retraction methods into the aggregateFunctions, such that on-going over window Aggregation can get benefit from it.

Issue Links

• links to: GitHub Pull Request #3470