Redis is a key-value storage system. Similar to Memcached, it supports relatively more stored value types, including string (string), list (linked list), set (set), zset (sorted set - ordered set) and hash (hash type). These data types all support push/pop, add/remove, intersection, union, difference, and richer operations, and these operations are all atomic.
You can learn that redis supports various different ways of sorting. Like memcached, data is cached in memory to ensure efficiency. The difference is that redis will periodically write updated data to disk or write modification operations to additional record files, and on this basis, master-slave (master-slave) synchronization is achieved.