[fix][broker] Fix ArrayIndexOutOfBoundsException due to race condition

[leizhiyuan]

Motivation

WARN ] 2022-03-10 17:27:26.976 [pulsar-io-36-20] ServerCnx - [/127.0.0.1:55561] Got exception java.lang.ArrayIndexOutOfBoundsException: 1
	at java.util.concurrent.CopyOnWriteArrayList.get(CopyOnWriteArrayList.java:388)
	at java.util.concurrent.CopyOnWriteArrayList.get(CopyOnWriteArrayList.java:397)
	at org.apache.pulsar.broker.service.AbstractDispatcherMultipleConsumers.getNextConsumer(AbstractDispatcherMultipleConsumers.java:121)
	at org.apache.pulsar.broker.service.nonpersistent.NonPersistentDispatcherMultipleConsumers.sendMessages(NonPersistentDispatcherMultipleConsumers.java:192)
	at org.apache.pulsar.broker.service.nonpersistent.NonPersistentTopic.lambda$publishMessage$1(NonPersistentTopic.java:182)
	at org.apache.pulsar.common.util.collections.ConcurrentOpenHashMap$Section.forEach(ConcurrentOpenHashMap.java:387)
	at org.apache.pulsar.common.util.collections.ConcurrentOpenHashMap.forEach(ConcurrentOpenHashMap.java:159)
	at org.apache.pulsar.broker.service.nonpersistent.NonPersistentTopic.publishMessage(NonPersistentTopic.java:176)
	at org.apache.pulsar.broker.service.Producer.publishMessageToTopic(Producer.java:210)
	at org.apache.pulsar.broker.service.Producer.publishMessage(Producer.java:149)
	at org.apache.pulsar.broker.service.ServerCnx.handleSend(ServerCnx.java:1321)
	at org.apache.pulsar.common.protocol.PulsarDecoder.channelRead(PulsarDecoder.java:232)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
	at io.netty.handler.flow.FlowControlHandler.dequeue(FlowControlHandler.java:200)

Modifications

assume consumerList is 1, if we use non persistent topic, and two producers publish messages, there will be two threads (pulsar-io)invoke this method, if one changed to 1, the other will faild.

currentConsumerRoundRobinIndex will be 1 and

        int currentRoundRobinConsumerPriority = consumerList.get(currentConsumerRoundRobinIndex).getPriorityLevel();

will throw ArrayIndexOutOfBoundsException

reproduce:

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 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
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package org.apache.pulsar.broker.service.nonpersistent;

import java.nio.charset.StandardCharsets;
import java.util.UUID;
import java.util.concurrent.TimeUnit;
import lombok.Cleanup;
import lombok.SneakyThrows;
import org.apache.pulsar.broker.service.BrokerTestBase;
import org.apache.pulsar.client.api.Consumer;
import org.apache.pulsar.client.api.Message;
import org.apache.pulsar.client.api.Producer;
import org.apache.pulsar.client.api.PulsarClient;
import org.apache.pulsar.client.api.SubscriptionType;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

@Test(groups = "broker")
public class NonPersistentTopicCocurrentTest extends BrokerTestBase {

    @BeforeMethod(alwaysRun = true)
    @Override
    protected void setup() throws Exception {
        super.baseSetup();
    }

    @AfterMethod(alwaysRun = true)
    @Override
    protected void cleanup() throws Exception {
        super.internalCleanup();
    }

    @SneakyThrows
    @Test
    public void test() {
        final String topicName = "non-persistent://prop/ns-abc/topic" + UUID.randomUUID();
        final String subName = "non-persistent";
        PulsarClient pulsarClient1 = newPulsarClient(lookupUrl.toString(), 0);
        @Cleanup
        Consumer<byte[]> consumer = pulsarClient1.newConsumer().topic(topicName)
                .subscriptionName(subName).subscriptionType(SubscriptionType.Shared).subscribe();
        PulsarClient pulsarClient2 = newPulsarClient(lookupUrl.toString(), 0);
        @Cleanup
        Producer<byte[]> producer1 = pulsarClient2.newProducer().topic(topicName).create();

        PulsarClient pulsarClient3 = newPulsarClient(lookupUrl.toString(), 0);
        @Cleanup
        Producer<byte[]> producer2 = pulsarClient3.newProducer().topic(topicName).create();

        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i < 10000; i++) {
                    producer1.sendAsync("msg".getBytes(StandardCharsets.UTF_8));
                }
            }
        });

        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i < 10000; i++) {
                    producer2.sendAsync("msg".getBytes(StandardCharsets.UTF_8));
                }
            }
        });
        t1.start();
        t2.start();

        while (true) {
            Message<byte[]> message = consumer.receive(1, TimeUnit.SECONDS);
            if (message == null) {
                break;
            } else {
                System.out.println(message);
            }
        }
    }
}

run sometimes, you will see in console

• [x] doc-not-needed

[github-actions[bot]]

@leizhiyuan:Thanks for your contribution. For this PR, do we need to update docs? (The PR template contains info about doc, which helps others know more about the changes. Can you provide doc-related info in this and future PR descriptions? Thanks)

[github-actions[bot]]

@leizhiyuan:Thanks for providing doc info!

[github-actions[bot]]

The pr had no activity for 30 days, mark with Stale label.

[wolfstudy]

/pulsarbot run-failure-checks

[leizhiyuan]

/pulsarbot run-failure-checks

[wolfstudy]

ping @eolivelli PTAL again, thanks

[github-actions[bot]]

The pr had no activity for 30 days, mark with Stale label.

[codelipenghui]

@eolivelli Please help review this PR again

[github-actions[bot]]

The pr had no activity for 30 days, mark with Stale label.

[leizhiyuan]

LGTM, but i'm not sure if we add synchronized will affect the performance?

we have tested whith load test in our produciton env。

[Jason918]

@eolivelli PTAL. This PR is blocked for a long time.

[congbobo184]

@leizhiyuan hi, I move this PR to release/2.9.5, if you have any questions, please ping me. thanks.

[tisonkun]

/pulsarbot run-failure-checks

[michaeljmarshall]

As discussed on the mailing list https://lists.apache.org/thread/w4jzk27qhtosgsz7l9bmhf1t7o9mxjhp, there is no plan to release 2.9.6, so I am going to remove the release/2.9.6 label

[leizhiyuan]

Since it takes a long time and the code differences are too large, I will close this PR.