ActiveMQ vs. Pulsar

Attribute	ActiveMQ	Pulsar
Messaging Protocol	OpenWire, AMQP, STOMP	MQTT, Pulsar Protocol
Language Support	Java, C++, Python, Ruby, Perl, PHP, .NET	Java, C++, Python, Go
Message Durability	Yes	Yes
Scalability	Horizontal scaling	Horizontal and vertical scaling
Partitioning	Yes	Yes
Message Retention	Configurable	Configurable

Introduction

Apache ActiveMQ and Apache Pulsar are both popular messaging systems used for building distributed systems. While they serve similar purposes, they have distinct features that make them suitable for different use cases. In this article, we will compare the attributes of ActiveMQ and Pulsar to help you understand their differences and choose the right messaging system for your needs.

Architecture

ActiveMQ is based on the Java Message Service (JMS) API and follows a traditional message broker architecture. It uses a central broker to route messages between producers and consumers. On the other hand, Pulsar is designed as a distributed messaging system with a multi-tenant architecture. It separates the serving and storage layers, allowing for better scalability and fault tolerance.

Scalability

ActiveMQ can be scaled horizontally by adding more brokers to distribute the message load. However, scaling ActiveMQ can be challenging as it requires careful configuration and monitoring to ensure optimal performance. Pulsar, on the other hand, is built for scalability from the ground up. It can easily scale to handle millions of messages per second by adding more serving and storage nodes without downtime.

Performance

ActiveMQ is known for its reliable message delivery but may suffer from performance issues when handling a high volume of messages. It uses a single-threaded architecture for message processing, which can become a bottleneck under heavy load. Pulsar, on the other hand, is designed for high performance and low latency. It uses a multi-threaded architecture and efficient data structures to achieve high throughput and low message delivery latency.

Features

ActiveMQ provides a wide range of features such as message persistence, message selectors, and message groups. It also supports various messaging protocols including JMS, AMQP, and MQTT. Pulsar, on the other hand, offers features like geo-replication, message deduplication, and schema enforcement. It also supports multiple messaging protocols and provides built-in support for streaming and event processing.

Reliability

ActiveMQ is known for its reliability and message durability. It supports persistent messaging and can recover from failures by storing messages in a persistent store. However, ActiveMQ may experience downtime during upgrades or maintenance. Pulsar, on the other hand, is designed for high availability and fault tolerance. It provides automatic failover and seamless upgrades without downtime, making it a more reliable choice for mission-critical applications.

Community and Support

ActiveMQ has a large and active community of users and contributors who provide support through forums, mailing lists, and documentation. It is a mature project with a long history of development and maintenance. Pulsar, on the other hand, is a newer project but has gained popularity due to its modern architecture and features. It has a growing community and is backed by a dedicated team of developers from the Apache Software Foundation.

Conclusion

In conclusion, both ActiveMQ and Pulsar are powerful messaging systems with their own strengths and weaknesses. ActiveMQ is a reliable and feature-rich messaging system suitable for traditional messaging use cases. Pulsar, on the other hand, is a scalable and high-performance messaging system designed for modern distributed systems. Depending on your requirements and use case, you can choose the messaging system that best fits your needs.