Package org.apache.flink.runtime.state.memory

Class ByteStreamStateHandle

java.lang.Object
org.apache.flink.runtime.state.memory.ByteStreamStateHandle
All Implemented Interfaces:
Serializable, StateObject, StreamStateHandle
public class ByteStreamStateHandle extends Object implements StreamStateHandle
A state handle that contains stream state in a byte array.
See Also:

  • Constructor Details

    • ByteStreamStateHandle

      public ByteStreamStateHandle(String handleName, byte[] data)
      Creates a new ByteStreamStateHandle containing the given data.

  • Method Details

    • 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.

    • getStreamStateHandleID

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

    • getData

      public byte[] getData()

    • getHandleName

      public String getHandleName()

    • 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

    • 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.

    • 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