[BEAM-5211] Flink Streaming ExecutableStage operator chain blocks grpc receiver threads

• Type: Bug
• Status: Resolved
• Priority: P2
• Resolution: Fixed
• Affects Version/s: 2.6.0
• Fix Version/s: 2.7.0
• Component/s: runner-flink
• Labels: portability
• Assignee: Thomas Weise
• Reporter: Thomas Weise
• Created: 23/Aug/18 22:49
• Updated: 16/May/20 13:31
• Resolved: 24/Aug/18 09:15

Description

The operator attempts to emit results as they are received, within the grpc thread, while the subtask thread is waiting for bundle completion. This leads to blocking of grpc threads and eventually deadlock when multiple stages are within an operator chain. Observed with wordcount, see attached stacktrace.

Issue Links

• links to: GitHub Pull Request #6271