public class FailureMapper<T> extends RichMapFunction<T,T> implements CheckpointListener
The total times to simulate a failure across multiple execution attempts of the operator can also be configured. Note that this also takes into account failures that were not triggered by this mapper, e.g. TaskManager failures.
|Constructor and Description|
|Modifier and Type||Method and Description|
The mapping method.
This method is called as a notification once a distributed checkpoint has been aborted.
Notifies the listener that the checkpoint with the given
close, getIterationRuntimeContext, getRuntimeContext, open, setRuntimeContext
public FailureMapper(long numProcessedRecordsFailureThreshold, long numCompleteCheckpointsFailureThreshold, int maxNumFailures)
public T map(T value) throws Exception
value- The input value.
Exception- This method may throw exceptions. Throwing an exception will cause the operation to fail and may trigger recovery.
public void notifyCheckpointComplete(long checkpointId) throws Exception
checkpointIdcompleted and was committed.
These notifications are "best effort", meaning they can sometimes be skipped. To behave
properly, implementers need to follow the "Checkpoint Subsuming Contract". Please see the
class-level JavaDocs for details.
Please note that checkpoints may generally overlap, so you cannot assume that the
notifyCheckpointComplete() call is always for the latest prior checkpoint (or snapshot) that
was taken on the function/operator implementing this interface. It might be for a checkpoint
that was triggered earlier. Implementing the "Checkpoint Subsuming Contract" (see above)
properly handles this situation correctly as well.
Please note that throwing exceptions from this method will not cause the completed checkpoint to be revoked. Throwing exceptions will typically cause task/job failure and trigger recovery.
checkpointId- The ID of the checkpoint that has been completed.
Exception- This method can propagate exceptions, which leads to a failure/recovery for the task. Not that this will NOT lead to the checkpoint being revoked.
public void notifyCheckpointAborted(long checkpointId)
Important: The fact that a checkpoint has been aborted does NOT mean that the data
and artifacts produced between the previous checkpoint and the aborted checkpoint are to be
discarded. The expected behavior is as if this checkpoint was never triggered in the first
place, and the next successful checkpoint simply covers a longer time span. See the
"Checkpoint Subsuming Contract" in the
class-level JavaDocs for
These notifications are "best effort", meaning they can sometimes be skipped.
This method is very rarely necessary to implement. The "best effort" guarantee, together with the fact that this method should not result in discarding any data (per the "Checkpoint Subsuming Contract") means it is mainly useful for earlier cleanups of auxiliary resources. One example is to pro-actively clear a local per-checkpoint state cache upon checkpoint failure.
checkpointId- The ID of the checkpoint that has been aborted.
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