Scaling to Billions: How RC Chat Delivers Massive Real-Time Messaging Concurrency

直播迅速发展成为全球数字娱乐的核心。从虚拟演唱会到大规模跨境电商直播，实时聊天已成为每一次互动体验的核心。但随着这种增长，也带来了巨大的技术挑战：
如何在保持互动完全实时的同时，支持无限用户和数十亿条消息？

在 RC，我们通过聊天 SDK 构建并部署了一个完全弹性、高可用性的聊天室架构。本文解析了背后的工程原理——揭示我们如何管理大规模用户规模、极端的消息并发以及无缝的服务连续性。

大规模实时聊天的两大核心挑战

1. 处理无限或近乎无限的用户

大型现场活动通常吸引数千万观众。在高峰时段，在线并发用户数可达数百万。

用户的输入、退出和状态变化给用户管理系统带来了持续的压力。这些作可激增至每秒数万次。如果没有细致的架构设计，这种流动水平会让系统不堪重负。

2. 实时管理消息洪流

庞大的受众自然会产生大量信息。拥有一百万活跃用户的聊天室会产生以下两者：

• 庞大的上游交通
• 下游配电流量更大

如果消息在峰值负载时被缓冲，就会产生延迟。结果是：消息-视频不同步——任何实时事件都严重失败。

这就是为什么实时分发是世界级聊天室系统的基础。

RC 无限聊天室的核心功能

高级消息处理

• 丰富消息类型：文本、图片、语音、文件，以及点赞、礼物或互动动画等自定义格式。
• 内置审核：敏感词汇过滤和反垃圾邮件工具。
• 智能分发逻辑：消息优先级、队列优化和灵活路由。

综合聊天室管理

• 完整用户生命周期：创建、加入、退出、销毁
• 用户控制：静音、封禁、查询、黑名单
• 允许名单支持：确保VIP或关键用户始终在线，并获得最大优先级消息
• 动态路由和容量决策的实时使用分析

基础：一个高可用性、横向可扩展的架构

我们的系统基于两个核心原则：
绝对可靠性和轻松的横向扩展。

Three-Layer Architecture

• Connection Layer: Maintains millions of persistent connections with minimal overhead.
• Business Layer: Distributed across multiple availability zones; chatroom and messaging services scale independently.
• Storage Layer: High-performance Redis for caching, persistence, and fast data access.

Engineered for Stability: Our High-Availability Blueprint

To ensure uninterrupted service during massive events, we support:

• Automatic failover
• Graceful service degradation
• Traffic governance and throttling
• Safe, quick rollbacks

When users send messages, they are routed to dedicated message services through consistent hashing. This optimizes cache performance and ensures predictable message flow. Zookeeper manages service registration and discovery to maintain system stability.

Seamless Scaling: How We Expand Without Downtime

Our scaling strategy combines pressure-testing insights with real-time business metrics. When traffic spikes:

1. New service instances come online automatically.
2. They load member lists, blocklists, and allowlists from Redis.
3. User migration is gradual and based on user activity.
4. Message services synchronize user state only when necessary.

This ensures elastic scalability with zero disruption to ongoing live events.

Why RC Excels: Distributed User Management + Efficient Message Delivery

Our breakthrough lies in decoupling the two most challenging components:
user management and message distribution.

Distributed User Management

• Chatroom services manage user lifecycle events.
• All state changes are written asynchronously into Redis.
• Message services maintain their own local list of active users.
• Synchronization only occurs when someone joins or leaves.

This eliminates central bottlenecks and allows virtually unlimited scaling.

Optimized Message Delivery

• Combination of push and pull mechanisms prevents duplication.
• Priority-based delivery ensures important messages arrive first.
• Default upstream limit is 200 messages/second (flexible for different business needs).

This approach enables us to deliver massive message volumes at extreme speed.

A Smooth Frontend Experience, Powered by a Modern Client SDK

A high-performance backend needs a client capable of rendering messages efficiently. Our SDK uses:

• MVVM architecture
• LiveData
• DiffUtil

These patterns support lightweight UI updates and smooth rendering.

In performance tests, the SDK handles 400 messages per second on mid-range devices without frame drops—ensuring the UI stays responsive during peak chat surges.

Conclusion: Powering the World’s Most Demanding Live Events

For platforms targeting large-scale live streaming, RC offers a proven, production-grade chatroom solution. Our high-availability architecture, elastic scaling, and distributed engineering approach provide:

• Unlimited user support
• Billion-level message concurrency
• Reliable real-time delivery
• Stable performance even in extreme scenarios

Trusted in top concerts, major shopping festivals, and global entertainment events, RC Chat delivers the infrastructure needed to create immersive, high-energy live experiences.