[FLINK-23035] Add explicit method to StateChangelogWriter to write metadata

• Type: Technical Debt
• Status: Resolved
• Priority: Minor
• Resolution: Resolved
• Fix Version/s: 1.17.0
• Component/s: Runtime / State Backends
• Labels: pull-request-available
• Assignee: Yanfei Lei
• Reporter: Roman Khachatryan
• Created: 18/Jun/21 12:44
• Updated: 16/Dec/22 07:37
• Resolved: 16/Dec/22 07:37

Description

Currently, metadata is written to the state changelog using the same StateChangelogWriter.append() method as data.

However, it doesn't belong to a specific group, and should be read first on recovery. Because of that, -1 is used.

An explicit append() without keygroup would be less fragile (probably still using -1 under the hood).

Issue Links

• is related to: FLINK-25842 [v2] FLIP-158: Generalized incremental checkpoints
• links to: GitHub Pull Request #21405