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ASF GitHub Bot commented on FLINK-2407: --------------------------------------- Github user gyfora commented on a diff in the pull request: https://github.com/apache/flink/pull/951#discussion_r35778711 --- Diff: flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/graph/StreamingJobGraphGenerator.java --- @@ -269,10 +270,19 @@ private void setVertexConfig(Integer vertexID, StreamConfig config, config.setNumberOfOutputs(nonChainableOutputs.size()); config.setNonChainedOutputs(nonChainableOutputs); config.setChainedOutputs(chainableOutputs); - config.setStateMonitoring(streamGraph.isCheckpointingEnabled()); - config.setStateHandleProvider(streamGraph.getStateHandleProvider()); + + config.setCheckpointingEnabled(streamGraph.isCheckpointingEnabled()); + if (streamGraph.isCheckpointingEnabled()) { + config.setCheckpointMode(streamGraph.getCheckpointingMode()); + config.setStateHandleProvider(streamGraph.getStateHandleProvider()); + } else { + // the at least once input handler is slightly cheaper (in the absence of checkpoints), + // so we use that one if checkpointing is not enabled + config.setCheckpointMode(CheckpointingMode.AT_LEAST_ONCE); --- End diff -- So we set an at_least_once handler even though we won't receive any barriers? Why not add an OFF mode which will use a "no-op barrier handler" or skip the barrier handler altogether? > Add an API switch to select between "exactly once" and "at least once" fault > tolerance > -------------------------------------------------------------------------------------- > > Key: FLINK-2407 > URL: https://issues.apache.org/jira/browse/FLINK-2407 > Project: Flink > Issue Type: Sub-task > Components: Streaming > Affects Versions: 0.10 > Reporter: Stephan Ewen > Assignee: Stephan Ewen > Fix For: 0.10 > > > Based on the addition of the BarrierTracker, we can add a switch to choose > between the two modes "exactly once" and "at least once". -- This message was sent by Atlassian JIRA (v6.3.4#6332)