Use Redis to reduce database access pressure and improve system performance

What is Redis

Redis is a key-value storage system. Similar to memcached, it supports storing more value types, including string (string), list (linked list), set (set), Zset (sorted set-ordered collection), and hash (hash type). These data types support Push/pop, Add/remove, and intersection-set and difference sets, and richer operations, and these operations are atomic. Based on this, Redis supports sorting in a variety of different ways. As with memcached, data is cached in memory to ensure efficiency. The difference is that Redis periodically writes the updated data to disk or writes the modified operation to the appended record file, and Master-slave (Master-Slave) synchronization is implemented on this basis.

Redis is a high-performance Key-value database. The emergence of Redis, to a large extent, compensates for the lack of memcached such key/value storage, in some cases can be a good complement to the relational database. It provides clients such as Java,c/c++,c#,php,javascript,perl,object-c,python,ruby,erlang, which is convenient to use.

Redis supports master-slave synchronization. Data can be synchronized from the primary server to any number of slave servers, from the server to the primary server that is associated with other slave servers. This enables Redis to perform single-layer tree replication. You can write to the data intentionally or unintentionally. Because of the full implementation of the publish/subscribe mechanism, you can subscribe to a channel and receive a complete message release record from the master server when the tree is synchronized anywhere from the database. Synchronization is helpful for the scalability and data redundancy of read operations. The role of using Redis in Javawebusing Redis, the main function is its cache, such as the computer's cache, when we want to access certain data, we first go to Redis to find out if it exists, if not, then access the database, and the data into Redis, The next visit can be read directly from the Redis, in a small project, you may not feel the performance of the promotion, but if there are hundreds of thousands of, millions of visits, the performance of the increase is a leap, greatly reducing the pressure on the database, but each time the data in the database changes, You must change the data in the Redis cache, or there will be an unsynchronized error, and Redis provides five data types: String,hash,list,set and Zset (sorted set). A variety of data can be stored. 　　

Before we start using Redis in Java, we need to make sure that we have the Redis service and the Java Redis driver installed and that Java is working properly on your machine.

(1) Java installation configuration can refer to our Java Development environment configuration

(2) The Redis service is installed;

Starting Redis service steps under Windows

Enter the Redis Bin directory:

Turn on Redis Services

After successful opening as follows:

Use Redis to reduce database access pressure and improve system performance