Package org.apache.flink.state.changelog

Interface StateChangeLogger<Value,Namespace>

Type Parameters:
Value - type of state (value)
Namespace - type of namespace
All Superinterfaces:
AutoCloseable, Closeable
All Known Subinterfaces:
KvStateChangeLogger<Value,Namespace>
@Internal public interface StateChangeLogger<Value,Namespace> extends Closeable
Logs changes to a state created by ChangelogKeyedStateBackend. The changes are intended to be stored durably, included into a checkpoint and replayed on recovery in case of failure.

Note that the order of updating the delegated state and logging it using this class usually doesn't matter. However in some cases an already updated state needs to be logged. Besides that, delegated state update is usually local and would fail faster. Therefore, consider updating the delegated state first and logging the change second.

If state update succeeds and changelog append fails immediately then the updated change is discarded as no checkpoints can proceed.

If changelog append fails asynchronously then subsequent checkpoints can only succeed after state materialization.

  • Method Details

    • valueUpdated

      void valueUpdated(Value newValue, Namespace ns) throws IOException
      State updated, such as by ListState.update(java.util.List<T>).
      Throws:
      IOException

    • valueUpdatedInternal

      void valueUpdatedInternal(Value newValue, Namespace ns) throws IOException
      State update internally (usually with a value that the user has no control over).
      Throws:
      IOException

    • valueAdded

      void valueAdded(Value addedValue, Namespace ns) throws IOException
      State added, such as append to list.addAll.
      Throws:
      IOException

    • valueCleared

      void valueCleared(Namespace ns) throws IOException
      State cleared.
      Throws:
      IOException

    • valueElementAdded

      void valueElementAdded(org.apache.flink.util.function.ThrowingConsumer<org.apache.flink.core.memory.DataOutputView,IOException> dataSerializer, Namespace ns) throws IOException
      State element added, such as append of a single element to a list.
      Throws:
      IOException

    • valueElementAddedOrUpdated

      void valueElementAddedOrUpdated(org.apache.flink.util.function.ThrowingConsumer<org.apache.flink.core.memory.DataOutputView,IOException> dataSerializer, Namespace ns) throws IOException
      State element added or updated, such as put into a map.
      Throws:
      IOException

    • valueElementRemoved

      void valueElementRemoved(org.apache.flink.util.function.ThrowingConsumer<org.apache.flink.core.memory.DataOutputView,IOException> dataSerializer, Namespace ns) throws IOException
      State element removed, such mapping removal from a map.
      Throws:
      IOException

    • resetWritingMetaFlag

      void resetWritingMetaFlag()
      Enable logging meta data before next writes.