[FLINK-5720] Deprecate "Folding" in all of DataStream API

• Type: Improvement
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 1.3.0, 1.4.0
• Component/s: API / DataStream
• Assignee: Chesnay Schepler
• Reporter: Aljoscha Krettek
• Created: 06/Feb/17 13:39
• Updated: 14/Sep/17 09:54
• Resolved: 10/May/17 07:16

Description

Folding is an operation that cannot be done incrementally in a distributed way and that also cannot be done on merging windows. Now that we have AggregatingState and aggregate operations we should deprecate folding in the APIs and deprecate FoldingState.

I suggest to remove folding completely in Flink 2.0

Issue Links

• links to: GitHub Pull Request #3816