Package org.apache.flink.runtime.state

Class KeyGroupsStateHandle

java.lang.Object
org.apache.flink.runtime.state.KeyGroupsStateHandle
All Implemented Interfaces:
Serializable, CompositeStateHandle, KeyedStateHandle, StateObject, StreamStateHandle
Direct Known Subclasses:
KeyGroupsSavepointStateHandle
public class KeyGroupsStateHandle extends Object implements StreamStateHandle, KeyedStateHandle
A handle to the partitioned stream operator state after it has been checkpointed. This state consists of a range of key group snapshots. A key group is subset of the available key space. The key groups are identified by their key group indices.
See Also:

  • Constructor Details

    • KeyGroupsStateHandle

      public KeyGroupsStateHandle(KeyGroupRangeOffsets groupRangeOffsets, StreamStateHandle streamStateHandle)
      Parameters:
      groupRangeOffsets - range of key-group ids that in the state of this handle
      streamStateHandle - handle to the actual state of the key-groups

  • Method Details

    • restore

      public static KeyGroupsStateHandle restore(KeyGroupRangeOffsets groupRangeOffsets, StreamStateHandle streamStateHandle, StateHandleID stateHandleId)

    • getGroupRangeOffsets

      public KeyGroupRangeOffsets getGroupRangeOffsets()
      Returns:
      the internal key-group range to offsets metadata

    • getDelegateStateHandle

      public StreamStateHandle getDelegateStateHandle()
      Returns:
      The handle to the actual states

    • getOffsetForKeyGroup

      public long getOffsetForKeyGroup(int keyGroupId)
      Parameters:
      keyGroupId - the id of a key-group. the id must be contained in the range of this handle.
      Returns:
      offset to the position of data for the provided key-group in the stream referenced by this state handle

    • getIntersection

      public KeyGroupsStateHandle getIntersection(KeyGroupRange keyGroupRange)
      Description copied from interface: KeyedStateHandle
      Returns a state over a range that is the intersection between this handle's key-group range and the provided key-group range.
      Specified by:
      getIntersection in interface KeyedStateHandle
      Parameters:
      keyGroupRange - a key group range to intersect.
      Returns:
      key-group state over a range that is the intersection between this handle's key-group range and the provided key-group range.

    • getStateHandleId

      public StateHandleID getStateHandleId()
      Description copied from interface: KeyedStateHandle
      Returns a unique state handle id to distinguish with other keyed state handles.

      If this state handle would be used as materialized part of ChangelogStateBackendHandle, it should persist this state handle id when serializing of checkpoint and deserialize it back to ensure the state handle id is constant.

      Specified by:
      getStateHandleId in interface KeyedStateHandle
      Returns:
      A unique state handle id.

    • getStreamStateHandleID

      public PhysicalStateHandleID getStreamStateHandleID()
      Specified by:
      getStreamStateHandleID in interface StreamStateHandle
      Returns:
      a unique identifier of this handle.

    • getKeyGroupRange

      public KeyGroupRange getKeyGroupRange()
      Description copied from interface: KeyedStateHandle
      Returns the range of the key groups contained in the state.
      Specified by:
      getKeyGroupRange in interface KeyedStateHandle

    • registerSharedStates

      public void registerSharedStates(SharedStateRegistry stateRegistry, 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:
      stateRegistry - The registry where shared states are registered.

    • discardState

      public void discardState() throws Exception
      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
      Throws:
      Exception

    • 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.

    • collectSizeStats

      public void collectSizeStats(StateObject.StateObjectSizeStatsCollector collector)
      Description copied from interface: StateObject
      Collects statistics about state size and location from the state object.
      Specified by:
      collectSizeStats in interface StateObject
      Parameters:
      collector - the statistics collector.

    • 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.

    • openInputStream

      public org.apache.flink.core.fs.FSDataInputStream openInputStream() throws IOException
      Description copied from interface: StreamStateHandle
      Returns an FSDataInputStream that can be used to read back the data that was previously written to the stream.
      Specified by:
      openInputStream in interface StreamStateHandle
      Throws:
      IOException

    • asBytesIfInMemory

      public Optional<byte[]> asBytesIfInMemory()
      Specified by:
      asBytesIfInMemory in interface StreamStateHandle
      Returns:
      Content of this handle as bytes array if it is already in memory.

    • maybeGetPath

      public Optional<org.apache.flink.core.fs.Path> maybeGetPath()
      Specified by:
      maybeGetPath in interface StreamStateHandle
      Returns:
      Path to an underlying file represented by this StreamStateHandle or Optional.empty() if there is no such file.

    • 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