This article brings you what is Redis? What are the application scenarios? It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
1. Introduction to Redis
Redis is an open source key-value single-threaded database that supports string, list, set, zset and hash type data.
Default port: 6379
Default number of databases: 16
2. Advantages:
1.nosql database has no correlation, simple data structure, and expansion Tables are easier
2.nosql has fast reading speed and fast processing of larger data
3. Applicable scenarios:
1 .Highly concurrent reading and writing of data
2. Reading and writing of massive data
Data with high scalability requirements
4. Uncomfortable scenarios:
1. Require transaction support (non-relational database)
2. Based on sql structured query storage, complex relationships
5 , Application scenarios
The following authors are Redis author @antirez. He describes some application scenarios that Redis is more suitable for. NoSQLFan briefly lists them here for everyone to have an overview:
For example, typically fetching the latest articles on your website, through the following method, we can put the IDs of the latest 5000 comments in the Redis List collection, and Get the part beyond the collection from the database
Use the LPUSH latest.comments
FUNCTION get_latest_comments(start,num_items): id_list = redis.lrange("latest.comments",start,start+num_items-1) IF id_list.length < num_items id_list = SQL_DB("SELECT ... ORDER BY time LIMIT ...") END RETURN id_list END
sorted set needs to be used. Set the value you want to sort to the score of the sorted set, and set the specific data to the corresponding value, you only need to execute one ZADD command each time.
3. Applications that need to accurately set the expiration timeFor example, you can set the score value of the sorted set mentioned above to the timestamp of the expiration time, then You can simply sort by the expiration time and clear the expired data regularly. Not only does it clear the expired data in Redis, you can completely regard the expiration time in Redis as an index of the data in the database, and use Redis to find out which data is needed. Delete upon expiration, and then accurately delete the corresponding records from the database. 4.priority queue system.
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