How to quickly understand Redis

1. Redis is one of the most popular NoSQL databases now. It is an open source written in ANSI C, contains a variety of data structures, supports the network, is based on memory, and has optional persistence. Key-value pair storage database. By default, Redis is a cache memory that is called for database use. It utilizes volatile memory and can provide users with complete persistence options and support for other data types.

2. Redis application scenarios include: cache system, counter, message queue system, ranking list, social network and real-time system.

3. Redis can use client APIs developed in all popular languages, such as C language, Ruby, Python, Java, JavaScript, etc.

4. Redis is famous for its durability. Its relational database backs up data at specified intervals in AOF mode, thereby taking a point-in-time snapshot of the data set and recording and writing (write) operations.

5. If the server does not subsequently execute the command, the Redis snapshot or Redis background saving process will intervene, so when any instruction reported as a primitive in random access memory (RAM) is in the disk snapshot, it will also Reported as primitives.

6. Generally speaking, Redis can handle up to 2³² keys, that is, hash, list, set and sorted set can use 2³² elements when they reach their peak. In actual testing, each instance can handle at least 250 million keys. Available memory is most likely the limiting factor on your machine/infrastructure using Redis.

7. In terms of data always remaining in memory, Redis has read and write operation capabilities that exceed those of conventional databases. This is one of the manifestations of its excellent performance and the reason why many developers choose it. .

Redis uses key-value pairs for data storage, in which certain types of data structures play the role of keys. Additionally, it allows objects to have their keys and values ​​capped at 512 megabytes. Redis hash table is a key hashing system that can be used to store key-value pairs.

9. The release of Redis 2.0 provides the function of data diffusion and applies the subscription/publish messaging protocol, which is the pub-sub model. This function is very practical.

10, Twitter, Pinterest and Github all use Redis projects. These are all well-known large companies in the industry. You can imagine how easy to use Redis is.

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