Shulou(Shulou.com)06/01 Report--

Today, the editor shares with you the reason why redis is so fast. I believe many people don't know much about it. In order to let you know more about the reason why redis is so fast, I summarize the following contents for you. Let's take a look at it. I'm sure you'll get something.

1. Based entirely on memory, most of the requests are purely memory operations, which is very fast. The data is stored in memory, and the advantage similar to HashMap,HashMap is that the time complexity of search and operation is O (1).

2. The data structure is simple and the data operation is simple. The data structure in Redis is specially designed.

3. Single thread avoids unnecessary context switching and competition conditions, and there is no CPU consumption caused by multi-process or multi-thread switching, there is no need to consider all kinds of locks, there is no lock release operation, and there is no performance consumption caused by possible deadlocks.

4. Using the multi-channel Istroke O multiplexing model, non-blocking IO

5. Different underlying models are used, and the underlying implementation between them and the application protocols for communication with clients are different. Redis directly builds its own VM mechanism, because the general system calls system functions, it will waste a certain amount of time to move and request.

The above points are easy to understand. Let's make a simple discussion on the multi-channel Icano reuse model.

(1) Multi-channel Istroke O multiplexing model

The multiplexing model of multiple streams uses the ability of select, poll, and epoll to monitor multiple streams' Icano events at the same time, blocking the current thread when idle, and waking up from the blocked state when one or more streams have Icano events, so the program polls all streams once (epoll polls only those streams that actually emit events) and processes only those that are ready in sequence. This practice avoids a large number of useless operations.

Here, "multiplex" refers to multiple network connections, and "multiplexing" refers to the reuse of the same thread. Using multi-channel IO multiplexing technology allows a single thread to process multiple connection requests efficiently (minimizing the time consumption of network IO), and Redis operates data in memory very fast, that is to say, in-memory operations will not become a bottleneck affecting Redis performance, which mainly makes Redis have high throughput.

What is the reason why redis is so fast is shared here, I hope the above content can have a certain reference value for you, you can apply what you have learned. If you like this article, you might as well share it for more people to see.

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