org.apache.rocketmq.common.stats.StatsItemSet#getAndCreateStatsItem has multi-thread problem #515
Description
The code below
public StatsItem getAndCreateStatsItem(final String statsKey) {
StatsItem statsItem = this.statsItemTable.get(statsKey);
if (null == statsItem) {
statsItem = new StatsItem(this.statsName, statsKey, this.scheduledExecutorService, this.log);
StatsItem prev = this.statsItemTable.put(statsKey, statsItem);
if (null != prev) {
// statsItem.init();
}
}
return statsItem;
}
has multi-thread problem. Because we can not ensure the atomicity of
StatsItem statsItem = this.statsItemTable.get(statsKey);
StatsItem prev = this.statsItemTable.put(statsKey, statsItem);
Here is the test case. The result is not always the correct one 20000.
public class BrokerStatsManagerTest {
private BrokerStatsManager brokerStatsManager;
private ThreadPoolExecutor executor;
@Before
public void init() {
brokerStatsManager = new BrokerStatsManager("DefaultCluster");
executor = new ThreadPoolExecutor(100, 200, 10, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(1000), new ThreadFactoryImpl("testMultiThread"));
}
@Test
public void testBrokerStatsManager() throws InterruptedException {
for(int i =0; i < 10000; i++) {
executor.submit(new Runnable() {
@Override
public void run() {
brokerStatsManager.incTopicPutNums("topicTest", 2, 1);
}
});
}
Thread.sleep(5000);
System.out.println(brokerStatsManager.getStatsItem(TOPIC_PUT_NUMS,"topicTest").getValue());
}
}