Uber's Scalable Architecture: Leveraging Redis and CDC for High-Performance Reads

Uber's massive user base and real-time operations demand a highly scalable and efficient infrastructure. To handle the demanding read-heavy workloads, Uber has implemented a sophisticated architecture that leverages Redis as a distributed in-memory data store and Change Data Capture (CDC) to ensure data consistency across multiple regions.

Key Components of Uber's Architecture

1. Microservices: Uber's architecture is based on a microservices approach, which breaks down complex applications into smaller, independent services. This allows for better scalability and maintainability.
2. Query Engine: The query engine is responsible for processing read requests and retrieving data from the appropriate data sources.
3. Stateless Compute: To enhance scalability and fault tolerance, Uber's compute layer is designed to be stateless, meaning it does not store any persistent data.
4. Redis Cache: Redis acts as a distributed in-memory cache, storing frequently accessed data for faster retrieval. This significantly reduces the load on the underlying database.
5. MySQL Database: MySQL serves as the primary storage engine for Uber's data. It provides a reliable and scalable solution for storing and managing large datasets.
6. Flux CDC: CDC is implemented using Flux, which captures changes made to the MySQL database and replicates them to Redis in real time. This ensures data consistency across the cache and the database.
7. Multi-Region Cache Warming: To improve performance in different geographical regions, Uber pre-loads frequently accessed data into Redis caches located in those regions. This reduces latency and improves user experience.
8. Redis and Database Sharding: To handle large datasets and high traffic, Uber distributes data across multiple Redis shards and MySQL shards. This improves scalability and performance.

How It Works

1. Read Requests: When a read request is received, the query engine first checks the Redis cache for the requested data. If the data is found in the cache, it is returned immediately.
2. Cache Miss: If the data is not found in the cache, the query engine fetches it from the MySQL database.
3. Write Operations: Write operations are directly written to the MySQL database.
4. CDC and Cache Invalidation: Flux CDC captures changes made to the MySQL database and replicates them to Redis. When a change occurs, the corresponding cache entry is invalidated to ensure data consistency.
5. Multi-Region Cache Warming: In different regions, frequently accessed data is pre-loaded into the local Redis cache. This reduces latency and improves performance for users in those regions.
6. Sharding: To handle large datasets and high traffic, both Redis and MySQL are sharded across multiple nodes. This improves scalability and performance.

Benefits of Uber's Architecture

• High Performance: The use of Redis as an in-memory cache significantly improves read performance.
• Scalability: The microservices architecture and sharding allow Uber to scale its infrastructure to handle increasing workloads.
• Data Consistency: CDC ensures data consistency between the cache and the database.
• Fault Tolerance: The stateless compute layer and distributed architecture improve fault tolerance.
• Reduced Latency: Multi-region cache warming reduces latency for users in different geographical regions.

By leveraging Redis, CDC, and a well-designed architecture, Uber has been able to create a highly scalable and efficient platform that can handle the demanding requirements of its real-time services.