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https://issues.apache.org/jira/browse/FLINK-19596?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17216541#comment-17216541
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Jiayi Liao commented on FLINK-19596:
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[~yunta] I didn't know there's already a JIRA before. Thanks for the remind and
you can re-assign it to me.
I agree with [~zjwang] that it may not be a good solution to couple
{{CompletedCheckpointStore.recover()}} with the types of failover. The best
solution comes to my mind for now is the same as [~zjwang]'s solution, letting
{{CompletedCheckpointStore}} recover itself if it's not been recovered yet,
when {{CheckpointCoordinator}} or other components trying to access the states
in {{CompletedCheckpointStore}}.
Specifically, I'm going to add new interface {{boolean
isCheckpointStoreInitialized()}} in {{CompletedCheckpointStore}} and allow
different implementations based on its root component.
> Do not recover CompletedCheckpointStore on each failover
> --------------------------------------------------------
>
> Key: FLINK-19596
> URL: https://issues.apache.org/jira/browse/FLINK-19596
> Project: Flink
> Issue Type: Improvement
> Components: Runtime / Checkpointing
> Affects Versions: 1.11.2
> Reporter: Jiayi Liao
> Priority: Major
>
> {{completedCheckpointStore.recover()}} in
> {{restoreLatestCheckpointedStateInternal}} could be a bottleneck on failover
> because the {{CompletedCheckpointStore}} needs to load HDFS files to
> instantialize the {{CompleteCheckpoint}} instances.
> The impact is significant in our case below:
> * Jobs with high parallelism (no shuffle) which transfer data from Kafka to
> other filesystems.
> * If a machine goes down, several containers and tens of tasks are affected,
> which means the {{completedCheckpointStore.recover()}} would be called tens
> of times since the tasks are not in a failover region.
> And I notice there is a "TODO" in the source codes:
> {code:java}
> // Recover the checkpoints, TODO this could be done only when there is a new
> leader, not on each recovery
> completedCheckpointStore.recover();
> {code}
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