Package org.apache.flink.streaming.runtime.watermarkstatus

Class HeapPriorityQueue<T extends HeapPriorityQueue.HeapPriorityQueueElement>

java.lang.Object
org.apache.flink.streaming.runtime.watermarkstatus.HeapPriorityQueue<T>
Type Parameters:
T - type of the contained elements.
public class HeapPriorityQueue<T extends HeapPriorityQueue.HeapPriorityQueueElement> extends Object
This class has similar functions with HeapPriorityQueue. It is introduced as the replacement of HeapPriorityQueue to be used in StatusWatermarkValve, to avoid affecting the performance of memory state backend.

The reason why the performance of memory state backend will be affected if we reuse the HeapPriorityQueue: In some scenarios, the HeapPriorityQueueElement will only have one implementation(used by memory state backend), which allows the jvm to inline its methods(getInternalIndex, setInternalIndex). If we reuse it in StatusWatermarkValve, it will cause it to have multiple implementations. Once there are multiple implementations, its methods will be difficult to be inlined by jvm, which will result in poor performance of memory state backend.

  • Constructor Details

    • HeapPriorityQueue

      public HeapPriorityQueue(@Nonnull HeapPriorityQueue.PriorityComparator<T> elementPriorityComparator, @Nonnegative int minimumCapacity)
      Creates an empty HeapPriorityQueue with the requested initial capacity.
      Parameters:
      elementPriorityComparator - comparator for the priority of contained elements.
      minimumCapacity - the minimum and initial capacity of this priority queue.

  • Method Details

    • adjustModifiedElement

      public void adjustModifiedElement(@Nonnull T element)

    • poll

      @Nullable public T poll()

    • peek

      @Nullable public T peek()

    • add

      public boolean add(@Nonnull T toAdd)

    • remove

      public boolean remove(@Nonnull T toRemove)

    • isEmpty

      public boolean isEmpty()

    • size

      public int size()

    • clear

      public void clear()
      Clears the queue.