[FLINK-11286] Support to send StreamStatus.IDLE for non-source operators

• Type: Improvement
• Status: Open
• Priority: Not a Priority
• Resolution: Unresolved
• Component/s: API / DataStream
• Labels: auto-deprioritized-major auto-deprioritized-minor auto-unassigned
• Assignee: Unassigned
• Reporter: vinoyang
• Created: 08/Jan/19 13:12
• Updated: 25/Dec/21 22:38

Description

Currently, only stream source tasks can be marked as temporary idle. But many times, this approach has limitations.

Considering such a scenario, there is a DAG as follows: source->map->filter->flatmap->keyBy->window, with a degree of parallelism of 10. Among them, the watermark is not sent by the source operator, but is downstream, such as flatmap. Every source subtask will not be idle. However, after the filter, some pipelines generate "idle". For example, there are 3 pipelines that will no longer have data sent downstream. At this time, we can't call the markAsTemporarilyIdle method to mark the current pipeline in the idle state. This will affect the downstream window.