[FLINK-31173] Fix several bugs in flink-ml-iteration module

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: ml-2.0.0, ml-2.1.0, ml-2.2.0
• Fix Version/s: ml-2.3.0
• Component/s: Library / Machine Learning
• Labels: pull-request-available
• Assignee: Zhipeng Zhang
• Reporter: Zhipeng Zhang
• Created: 22/Feb/23 02:31
• Updated: 20/Apr/23 09:48
• Resolved: 20/Apr/23 08:40

Description

In flink-ml-iteration, there are several bugs as follows:

1. TailOperator should have one input operator. We have added a Tail operator to increment the epoch watermark at each iteration. We have made an assumption that each Tail operator have only one input and did not align the epoch watermarks from different inputs. This assumption might not be true if the input is an `union`.
2. ProxyOperatorStateBackend does not correctly initialize the state descriptor.

Issue Links

• links to: GitHub Pull Request #216