Why is single threaded Redis so fast

Redis is a high-performance, in-memory key-value database known for its impressive speed, achieving around 100,000 queries per second on a single machine despite its single-threaded architecture. The reasons for its efficiency include data storage in memory, efficient data structures, a single-threaded design, and non-blocking I/O. By storing data in memory, Redis eliminates the overhead associated with disk I/O. Its five data types—String, List, Hash, Set, and SortedSet—are optimized for speed through various underlying data structures. The single-threaded model reduces context switching and CPU consumption, avoiding race conditions and locking issues, which can hinder performance. Although Redis can block if a command takes too long, its design allows for efficient handling of multiple client connections through non-blocking I/O multiplexing. This model enables Redis to manage multiple network connections effectively, ensuring high performance. Redis 6.0 introduced multi-threading to address network I/O bottlenecks, allowing for concurrent handling of network data while maintaining single-threaded command execution to avoid concurrency issues. Multi-threading can be enabled in the configuration file, with recommendations for the number of threads based on the machine's core count.

- Redis achieves high performance through a single-threaded architecture.

- Data is stored in memory, eliminating disk I/O overhead.

- Non-blocking I/O multiplexing allows efficient handling of multiple connections.

- Redis 6.0 introduced multi-threading to improve network I/O performance.

- Command execution remains single-threaded to avoid concurrency issues.