Package org.apache.flink.runtime.checkpoint

Class OperatorSubtaskState

java.lang.Object
org.apache.flink.runtime.checkpoint.OperatorSubtaskState
All Implemented Interfaces:
Serializable, CompositeStateHandle, StateObject
Direct Known Subclasses:
FinishedOperatorSubtaskState
public class OperatorSubtaskState extends Object implements CompositeStateHandle
This class encapsulates the state for one parallel instance of an operator. The complete state of a (logical) operator (e.g. a flatmap operator) consists of the union of all OperatorSubtaskStates from all parallel tasks that physically execute parallelized, physical instances of the operator.

The full state of the logical operator is represented by OperatorState which consists of OperatorSubtaskStates.

Typically, we expect all collections in this class to be of size 0 or 1, because there is up to one state handle produced per state type (e.g. managed-keyed, raw-operator, ...). In particular, this holds when taking a snapshot. The purpose of having the state handles in collections is that this class is also reused in restoring state. Under normal circumstances, the expected size of each collection is still 0 or 1, except for scale-down. In scale-down, one operator subtask can become responsible for the state of multiple previous subtasks. The collections can then store all the state handles that are relevant to build up the new subtask state.

See Also:

  • Method Details

    • getManagedOperatorState

      public StateObjectCollection<OperatorStateHandle> getManagedOperatorState()

    • getRawOperatorState

      public StateObjectCollection<OperatorStateHandle> getRawOperatorState()

    • getManagedKeyedState

      public StateObjectCollection<KeyedStateHandle> getManagedKeyedState()

    • getRawKeyedState

      public StateObjectCollection<KeyedStateHandle> getRawKeyedState()

    • getInputChannelState

      public StateObjectCollection<InputChannelStateHandle> getInputChannelState()

    • getResultSubpartitionState

      public StateObjectCollection<ResultSubpartitionStateHandle> getResultSubpartitionState()

    • getInputRescalingDescriptor

      public InflightDataRescalingDescriptor getInputRescalingDescriptor()

    • getOutputRescalingDescriptor

      public InflightDataRescalingDescriptor getOutputRescalingDescriptor()

    • getDiscardables

      public List<StateObject> getDiscardables()

    • discardState

      public void discardState()
      Description copied from interface: StateObject
      Discards the state referred to and solemnly owned by this handle, to free up resources in the persistent storage. This method is called when the state represented by this object will not be used anymore.
      Specified by:
      discardState in interface StateObject

    • registerSharedStates

      public void registerSharedStates(SharedStateRegistry sharedStateRegistry, long checkpointID)
      Description copied from interface: CompositeStateHandle
      Register both newly created and already referenced shared states in the given SharedStateRegistry. This method is called when the checkpoint successfully completes or is recovered from failures.

      After this is completed, newly created shared state is considered as published is no longer owned by this handle. This means that it should no longer be deleted as part of calls to StateObject.discardState(). Instead, StateObject.discardState() will trigger an unregistration from the registry.

      Specified by:
      registerSharedStates in interface CompositeStateHandle
      Parameters:
      sharedStateRegistry - The registry where shared states are registered.

    • getCheckpointedSize

      public long getCheckpointedSize()
      Description copied from interface: CompositeStateHandle
      Returns the persisted data size during checkpoint execution in bytes. If incremental checkpoint is enabled, this value represents the incremental persisted data size, and usually smaller than StateObject.getStateSize(). If the size is unknown, this method would return same result as StateObject.getStateSize().
      Specified by:
      getCheckpointedSize in interface CompositeStateHandle
      Returns:
      The persisted data size during checkpoint execution in bytes.

    • getStateSize

      public long getStateSize()
      Description copied from interface: StateObject
      Returns the size of the state in bytes. If the size is not known, this method should return 0.

      The values produced by this method are only used for informational purposes and for metrics/monitoring. If this method returns wrong values, the checkpoints and recovery will still behave correctly. However, efficiency may be impacted (wrong space pre-allocation) and functionality that depends on metrics (like monitoring) will be impacted.

      Note for implementors: This method should not perform any I/O operations while obtaining the state size (hence it does not declare throwing an IOException). Instead, the state size should be stored in the state object, or should be computable from the state stored in this object. The reason is that this method is called frequently by several parts of the checkpointing and issuing I/O requests from this method accumulates a heavy I/O load on the storage system at higher scale.

      Specified by:
      getStateSize in interface StateObject
      Returns:
      Size of the state in bytes.

    • isFinished

      public boolean isFinished()

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • hasState

      public boolean hasState()

    • toBuilder

      public OperatorSubtaskState.Builder toBuilder()

    • builder

      public static OperatorSubtaskState.Builder builder()