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https://issues.apache.org/jira/browse/FLINK-2407?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14646336#comment-14646336
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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".
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