jerrypeng commented on a change in pull request #6791:
URL: https://github.com/apache/pulsar/pull/6791#discussion_r413394891
##########
File path:
pulsar-broker/src/main/java/org/apache/pulsar/broker/service/HashRangeAutoSplitStickyKeyConsumerSelector.java
##########
@@ -18,86 +18,64 @@
*/
package org.apache.pulsar.broker.service;
-import
org.apache.pulsar.broker.service.BrokerServiceException.ConsumerAssignException;
-import org.apache.pulsar.common.util.Murmur3_32Hash;
-
import java.util.Collections;
-import java.util.HashMap;
import java.util.Map;
-import java.util.Map.Entry;
-import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.NavigableMap;
+import java.util.TreeMap;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import
org.apache.pulsar.broker.service.BrokerServiceException.ConsumerAssignException;
+import org.apache.pulsar.common.util.Murmur3_32Hash;
/**
* This is a consumer selector based fixed hash range.
*
- * 1.Each consumer serves a fixed range of hash value
- * 2.The whole range of hash value could be covered by all the consumers.
- * 3.Once a consumer is removed, the left consumers could still serve the
whole range.
- *
- * Initializing with a fixed hash range, by default 2 << 5.
- * First consumer added, hash range looks like:
- *
- * 0 -> 65536(consumer-1)
- *
- * Second consumer added, will find a biggest range to split:
- *
- * 0 -> 32768(consumer-2) -> 65536(consumer-1)
- *
- * While a consumer removed, The range for this consumer will be taken over
- * by other consumer, consumer-2 removed:
- *
- * 0 -> 65536(consumer-1)
- *
- * In this approach use skip list map to maintain the hash range and consumers.
- *
- * Select consumer will return the ceiling key of message key hashcode % range
size.
- *
+ * The implementation uses consistent hashing to evenly split, the
+ * number of keys assigned to each consumer.
*/
public class HashRangeAutoSplitStickyKeyConsumerSelector implements
StickyKeyConsumerSelector {
- private final int rangeSize;
+ private final ReadWriteLock rwLock = new ReentrantReadWriteLock();
- private final ConcurrentSkipListMap<Integer, Consumer> rangeMap;
- private final Map<Consumer, Integer> consumerRange;
+ // Consistent-Hash ring
+ private final NavigableMap<Integer, Consumer> hashRing;
- public HashRangeAutoSplitStickyKeyConsumerSelector() {
- this(DEFAULT_RANGE_SIZE);
- }
+ private final int numberOfPOints;
- public HashRangeAutoSplitStickyKeyConsumerSelector(int rangeSize) {
- if (rangeSize < 2) {
- throw new IllegalArgumentException("range size must greater than
2");
- }
- if (!is2Power(rangeSize)) {
- throw new IllegalArgumentException("range size must be nth power
with 2");
- }
- this.rangeMap = new ConcurrentSkipListMap<>();
- this.consumerRange = new HashMap<>();
- this.rangeSize = rangeSize;
+ public HashRangeAutoSplitStickyKeyConsumerSelector(int numberOfPOints) {
+ this.hashRing = new TreeMap<>();
+ this.numberOfPOints = numberOfPOints;
}
@Override
- public synchronized void addConsumer(Consumer consumer) throws
ConsumerAssignException {
- if (rangeMap.size() == 0) {
- rangeMap.put(rangeSize, consumer);
- consumerRange.put(consumer, rangeSize);
- } else {
- splitRange(findBiggestRange(), consumer);
+ public void addConsumer(Consumer consumer) throws ConsumerAssignException {
+ rwLock.writeLock().lock();
+ try {
+ // Insert multiple points on the hash ring for every consumer
+ // The points are deterministically added based on the hash of the
consumer name
+ for (int i = 0; i < numberOfPOints; i++) {
Review comment:
"numberOfPoints"
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