[FLINK-26079] [Changelog] Disallow recovery from non-changelog checkpoints

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 1.15.0
• Component/s: Runtime / Configuration, Runtime / State Backends
• Labels: pull-request-available
• Assignee: Roman Khachatryan
• Reporter: Roman Khachatryan
• Created: 10/Feb/22 21:14
• Updated: 21/Feb/22 11:29
• Resolved: 16/Feb/22 15:50

Description

Extracted from FLINK-25872. 

The issue is with the CLAIM mode:
> Because discarding an initial checkpoint will invalidate its "private" state which might be in use by future checkpoints.
> Normally, changelog backend wraps it and registers with tjhe SharedStateRegistry.
> But when recovering from non-changelog checkpoint, it is first added to the Checkpoint store, and wrapping in subsequent checkpoints doesn't help.

NO_CLAIM mode is not supported.
LEGACY could work.

But it's difficult to differentiate between the modes on TM, where backend type is reliably known (see the discussion below).

CANONICAL non-changelog savepoints must still be supported.

Issue Links

• blocks: FLINK-21352 FLIP-158: Generalized incremental checkpoints
• is caused by: FLINK-25872 Restoring from non-changelog checkpoint with changelog state-backend enabled in CLAIM mode discards state in use
• links to: GitHub Pull Request #18735