Redis (Remote Dictionary Server) is an open source, memory-based, key-value storage system. Redis provides the implementation of multiple data structures, including strings, hash tables, lists, sets, and ordered sets. Redis has many advantages: high performance, scalability, support for rich data structures and commands, etc. As a result, it has become the solution of choice for many businesses, especially when it comes to real-time data processing.
The high performance of Redis is reflected in the following aspects:
In order to obtain high performance, Redis uses memory to store data , which makes it fast to read and write data. Redis also uses a persistence method called RDB (Redis Database) to save data in memory to the hard disk in the form of snapshots to avoid data loss during system downtime.
Redis supports rich data structures and commands, such as strings, hash tables, lists, sets, ordered sets, etc. These data structures provide more options for data processing.
Redis can implement asynchronous operation. It can convert client requests into commands, put them in a queue, and execute them one by one in order. . This avoids competition and conflicts caused by multiple clients making requests at the same time.
The following are some examples of using redis:
import redis conn = redis.Redis(host='localhost', port=6379, db=0) # 写入一个字符串 conn.set('key', 'value') # 读取字符串 print(conn.get('key'))
In this example, we use the set and set provided by redis get method to implement string storage.
import redis conn = redis.Redis(host='localhost', port=6379, db=0) # 写入一个哈希表 conn.hset('hash_key', 'field1', 'value1') conn.hset('hash_key', 'field2', 'value2') # 读取哈希表 print(conn.hgetall('hash_key'))
In this example, we use the hset and hgetall methods provided by redis to store and read hash tables. In a hash table, both field and value are string types.
import redis conn = redis.Redis(host='localhost', port=6379, db=0) # 写入一个列表 conn.rpush('list_key', 'value1') conn.rpush('list_key', 'value2') conn.rpush('list_key', 'value3') # 读取一个列表 print(conn.lrange('list_key', 0, -1))
In this example, we use the rpush and lrange methods provided by redis to store and read the list. In a list, each element is of type string.
import redis conn = redis.Redis(host='localhost', port=6379, db=0) # 写入一个集合 conn.sadd('set_key', 'value1') conn.sadd('set_key', 'value2') # 读取一个集合 print(conn.smembers('set_key'))
In this example, we use the sadd and smembers methods provided by redis to store and read collections. In a collection, each element is of unique string type.
import redis conn = redis.Redis(host='localhost', port=6379, db=0) # 写入一个有序集合 conn.zadd('zset_key', {'value1': 1, 'value2': 2}) # 读取一个有序集合 print(conn.zrange('zset_key', 0, -1))
In this example, we use the zadd and zrange methods provided by redis to store and read ordered sets. In an ordered set, each element is of unique string type, and each element has a given score.
The above are some common operation examples of Redis. Through these examples, we can find that Redis is not only a key-value storage system, it also provides the implementation of a variety of data structures, providing real-time data processing More flexible options.
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