Why is single threaded Redis so fast

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2024-09-04 03:30:04

Redis is a high-performance, in-memory key-value database. According to official test reports, it can support around 100,000 QPS (queries per second) on a single machine. However, Redis uses a single-threaded architecture in its design.

Why does Redis still have such high performance with a single-threaded design? Wouldn't it be better to use multiple threads for concurrent request processing?

In this article, let's explore why Redis has a single-threaded architecture and still maintains its speed. The focus is on the following four aspects:

Redis is completely based on memory, with data stored in memory. The vast majority of requests are pure memory operations, which are extremely fast. Compared with traditional disk file data storage, Redis avoids the overhead of reading data from disk into memory through disk I/O.

Using a single thread saves a lot of time on context switching and CPU consumption, there are no race conditions, no need to consider various locking problems, and no locking and unlocking operations that could cause performance overhead due to deadlocks. Additionally, it allows the use of various "thread-unsafe" commands, such as Lpush.