[FLINK-14344] A preparation for snapshotting master hook state asynchronously

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.10.0
• Component/s: Runtime / Checkpointing
• Labels: pull-request-available
• Release Note: The contract of `MasterTriggerRestoreHook#triggerCheckpoint` (@PublicEvolving api) has changed - we now require it to be non-blocking. Any heavy operation should be executed asynchronously, for example using the given executor.
• Assignee: Biao Liu
• Reporter: Biao Liu
• Created: 08/Oct/19 08:20
• Updated: 13/Nov/19 10:52
• Resolved: 13/Nov/19 10:52

Description

Currently we snapshot the master hook state synchronously. As a part of reworking threading model of CheckpointCoordinator, we have to make this non-blocking to satisfy the requirement of running in main thread.

The behavior of snapshotting master hook state is similar to task state snapshotting. Master state snapshotting is taken before task state snapshotting. Because in master hook, there might be external system initialization which task state snapshotting might depend on.

Issue Links

• links to: GitHub Pull Request #9885