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

Class HeapPriorityQueue<T extends org.apache.flink.streaming.runtime.watermarkstatus.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 org.apache.flink.streaming.runtime.watermarkstatus.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 Summary

Constructors

Constructor	Description
HeapPriorityQueue(org.apache.flink.streaming.runtime.watermarkstatus.HeapPriorityQueue.PriorityComparator<T> elementPriorityComparator, int minimumCapacity)	Creates an empty HeapPriorityQueue with the requested initial capacity.

Method Summary

Modifier and Type	Method	Description
boolean	add(T toAdd)
void	adjustModifiedElement(T element)
void	clear()	Clears the queue.
boolean	isEmpty()
T	peek()
T	poll()
boolean	remove(T toRemove)
int	size()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HeapPriorityQueue

public HeapPriorityQueue(@Nonnull
                         org.apache.flink.streaming.runtime.watermarkstatus.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 Detail

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.