[FLINK-12693] Store state per key-group in CopyOnWriteStateTable

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Implemented
• Component/s: Runtime / State Backends
• Labels: pull-request-available
• Assignee: PengFei Li
• Reporter: Yu Li
• Created: 31/May/19 13:09
• Updated: 31/May/20 11:53
• Resolved: 09/Jul/19 07:22

Description

Since we propose to use KeyGroup as the unit of spilling/loading, the first step is to store state per key-groups. Currently NestedMapsStateTable natively supports this, so we only need to refine CopyOnWriteStateTable

The main efforts required here is to extract the customized hash-map out of CopyOnWriteStateTable then use such a hash-map as the state holder for each KeyGroup. Whereafter we could extract some common logic out into StateTable.

Issue Links

• blocks: FLINK-12698 Implement a SpillLoadManager
• links to: GitHub Pull Request #8611