Apache RocketMQ

What is Apache RocketMQ?

Apache RocketMQ is a distributed messaging and streaming platform originally developed by Alibaba Group. It's designed for high-throughput, low-latency messaging with strong consistency guarantees. RocketMQ powers critical systems at Alibaba, handling trillions of messages daily during events like Singles' Day.

Unlike other message queues, RocketMQ provides unique features like transactional messaging, scheduled message delivery, and message filtering. It combines the best of traditional message queues with modern streaming capabilities, making it ideal for e-commerce, financial services, and IoT applications.

🏗️ RocketMQ Architecture

⭐ Unique Features

// Send transactional message
TransactionMQProducer producer = new TransactionMQProducer("transaction_producer");
producer.setTransactionListener(new LocalTransactionExecuter());
producer.start();

Message message = new Message("TopicTest", "TagA", "Hello RocketMQ".getBytes());
SendResult result = producer.sendMessageInTransaction(message, null);

// Producer sends with properties
Message message = new Message("TopicTest", "TagA", "Hello".getBytes());
message.putUserProperty("category", "electronics");
message.putUserProperty("price", "100");

// Consumer filters messages
consumer.subscribe("TopicTest", MessageSelector.bySql("category = 'electronics' AND price > 50"));

// Schedule message for 10 seconds later
Message message = new Message("TopicTest", "TagA", "Delayed message".getBytes());
message.setDelayTimeLevel(3); // 10 seconds delay

SendResult result = producer.send(message);

// Send ordered messages
String orderId = "ORDER_001";
for (int i = 0; i < 5; i++) {
    Message message = new Message("OrderTopic", ("Order step " + i).getBytes());
    // Use orderId as selector to ensure same queue
    producer.send(message, new MessageQueueSelector() {
        public MessageQueue select(List<MessageQueue> queues, Message msg, Object arg) {
            String orderId = (String) arg;
            int index = orderId.hashCode() % queues.size();
            return queues.get(Math.abs(index));
        }
    }, orderId);
}

🌍 Real-World Examples

💡 Best Practices

⚡ Performance Comparison