[FLINK-9486] Introduce TimerState in keyed state backend

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Implemented
• Fix Version/s: 1.6.0
• Component/s: Runtime / State Backends
• Labels: pull-request-available
• Assignee: Stefan Richter
• Reporter: Stefan Richter
• Created: 01/Jun/18 12:40
• Updated: 11/Sep/18 13:48
• Resolved: 09/Jul/18 14:14

Description

This is the first implementation subtask.

Goal of this PR is to introduce a timer state that is registered with the keyed state backend, similar to other forms of keyed state.

For the HeapKeyedStateBackend, this state lives on the same level as the StateTable that hold other forms of keyed state, and the implementation is basically backed by InternalTimerHeap.

For RocksDBKeyedStateBackend, in this first step, we also introduce this state, outside of RocksDB and based upon InternalTimerHeap. This is an intermediate state, and we will later also implement the alternative to store the timers inside a column families in RocksDB. However, by taking this step, we could also still offer the option to have RocksDB state with heap-based timers.

Issue Links

• links to: GitHub Pull Request #6276