[FLINK-4445] Ignore unmatched state when restoring from savepoint

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.1.1
• Fix Version/s: 1.1.4, 1.2.0
• Component/s: Runtime / State Backends
• Assignee: Ufuk Celebi
• Reporter: Ufuk Celebi
• Created: 22/Aug/16 08:45
• Updated: 02/Nov/16 07:18
• Resolved: 02/Nov/16 07:17

Description

When currently submitting a job with a savepoint, we require that all state is matched to the new job. Many users have noted that this is overly strict. I would like to loosen this and allow savepoints to be restored without matching all state.

The following options come to mind:

(1) Keep the current behaviour, but add a flag to allow ignoring state when restoring, e.g. bin/flink -s <savepoint> --ignoreUnmatchedState. This would be non-API breaking.

(2) Ignore unmatched state and continue. Additionally add a flag to be strict about checking the state, e.g. bin/flink -s <savepoint> --strict. This would be API-breaking as the default behaviour would change. Users might be confused by this because there is no straight forward way to notice that nothing has been restored.

I'm not sure what's the best thing here. gyfora, aljoscha What do you think?

Issue Links

• links to: GitHub Pull Request #2712
• links to: GitHub Pull Request #2713