Gyula Fora created FLINK-2390: --------------------------------- Summary: Replace iteration timeout with algorithm for detecting termination Key: FLINK-2390 URL: https://issues.apache.org/jira/browse/FLINK-2390 Project: Flink Issue Type: New Feature Components: Streaming Reporter: Gyula Fora Fix For: 0.10
Currently the user can set a timeout which will shut down the iteration source/sink nodes if no new data is received during that time to allow program termination in iterative streaming jobs. This method is used due to the non-trivial nature of termination in iterative streaming jobs. While termination is not a main concern in long running streaming jobs, this behaviour makes iterative tests non-deterministic and they often fail on travis due to the timeout. Also setting a timeout can cause jobs to terminate prematurely. I propose to remove iteration timeouts and replace it with the following algorithm for detecting termination: -We first identify loop edges in the jobgraph (the channels from the iteration sources to the head operators) -Once the head operators (the ones with loop input) finish with all their non-loop inputs they broadcast a marker to their outputs. -Each operator will broadcast a marker once it received a marker from all its non-finished inputs -Iteration sources are terminated when they receive 2 consecutive markers without receiving any record in-between The idea behind the algorithm is to find out when no more outputs are generated from the operators inside an iteration after their normal inputs are finished. -- This message was sent by Atlassian JIRA (v6.3.4#6332)