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https://issues.apache.org/jira/browse/FLINK-20427?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17242413#comment-17242413
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Till Rohrmann commented on FLINK-20427:
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No, it is only a problem if a regional failover occurs where we don't resume
from the latest checkpoint/savepoint. This can, however, easily happen in
normal operation mode and, hence, I believe that we should not allow resuming
from an earlier checkpoint/savepoint.
> Remove CheckpointConfig.setPreferCheckpointForRecovery because it can lead to
> data loss
> ---------------------------------------------------------------------------------------
>
> Key: FLINK-20427
> URL: https://issues.apache.org/jira/browse/FLINK-20427
> Project: Flink
> Issue Type: Bug
> Components: API / DataStream, Runtime / Checkpointing
> Affects Versions: 1.12.0
> Reporter: Till Rohrmann
> Priority: Critical
> Fix For: 1.13.0
>
>
> The {{CheckpointConfig.setPreferCheckpointForRecovery}} allows to configure
> whether Flink prefers checkpoints for recovery if the
> {{CompletedCheckpointStore}} contains savepoints and checkpoints. This is
> problematic because due to this feature, Flink might prefer older checkpoints
> over newer savepoints for recovery. Since some components expect that the
> always the latest checkpoint/savepoint is used (e.g. the
> {{SourceCoordinator}}), it breaks assumptions and can lead to
> {{SourceSplits}} which are not read. This effectively means that the system
> loses data. Similarly, this behaviour can cause that exactly once sinks might
> output results multiple times which violates the processing guarantees.
> Hence, I believe that we should remove this setting because it changes
> Flink's behaviour in some very significant way potentially w/o the user
> noticing.
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