Introduction to redis

1.1 Redis brief introduction

 　　Redis It's open source （BSD The license ）, Memory storage data structure server , It can be used as a database , Caching and message queuing agents . It supports strings 、 Hashtable 、 list 、 aggregate 、 Ordered set , Bitmap ,hyperloglogs And so on . Built in replication 、Lua Script 、LRU Take back 、 Transactions and different levels of disk persistence , At the same time through Redis Sentinel Provide high availability , adopt Redis Cluster Provide automatic zoning .

　　 It can be used for general projects .

1.2 Redis Information

 　　Redis There are still a lot of information , First of all, recommend Redis Information of Chinese website , Other

1.2.1 Preliminary tutorial

　　Redis course ：http://www.runoob.com/redis/redis-tutorial.html, Novice tutorial , It's very detailed , After reading, it's basically right Redis Have a comprehensive understanding . Links to each part ：

　　Redis course Redis brief introduction Redis install Redis To configure Redis data type

　　Redis command Redis key (key) Redis character string (String) Redis Hash (Hash) Redis list (List) Redis aggregate (Set) Redis Ordered set (sorted set) Redis HyperLogLog Redis Publish subscribe Redis Business Redis Script Redis Connect Redis The server

　　Redis Data backup and recovery Redis Security Redis Performance testing Redis Client connection Redis Pipeline technology Redis Partition Java Use Redis PHP Use Redis

1.2.2 Other tutorials

　　 All command parsing ：http://www.redis.net.cn/order/, You can inquire if you don't understand .

Two 、Redis Comparison with similar products

　　 according to Redis An introduction to the ,Redis It can be used as a database , Caching and message queuing agents , So when you plan to use these functions , Consider the comparison with other products , Choose a better one .

1.1 As a database, compare it

　　Redis It can be used as a database , It can be seen as a key/value Type database , because Redis The data in memory will be written to the hard disk according to the configuration timing , In this way, you can still recover even after restarting , But there are several shortcomings to consider ：

Redis Can only store key/value type , although value There can be many types of , But for related record query , No, Oracle/Mysql convenient .

Redis There is a certain time interval for memory data to be written to the hard disk , Data may be lost during this interval , Although various modes will be introduced later to ensure the possibility of data loss , But it is still possible , Therefore, it is not recommended to use if there are strict requirements on data Redis As a database .

1.2 As a comparison with cache

　　 I think Redis My job is caching , Also available as a cache are Ehcache、Memcached . There is a blog that introduces it in detail ：http://blog.csdn.net/jationxiaozi/article/details/8509732. Let me just summarize , Just talk about their biggest features , Reading speed is no longer considered , After all, it can be used as a caching tool for mutual comparison , The speed will not be too bad , List only the outstanding advantages and disadvantages , Listed means no other ：

Ehcache

It's a Java Open source project , The way to use it is to introduce a jar package , Very convenient

Memcached 

If multithreading mode is enabled , The reading speed will be greatly improved

Data will only be stored in memory , Data cannot be recovered after hanging up

Redis

The data structure is very rich , character string 、hash list 、list、Set wait

Support the master and slave ,Sentinal, Slicing and other advanced features , For load balancing and disaster recovery , High availability

Clients that support almost all languages

　　 Choose the most suitable according to your needs .

1.3 As a message queue, compare it

　　Redis It can also be used as a message queue , The same function is better Kafka, The simple comparison is as follows ：

Redis

It can only be said that it has the function of publishing and subscribing , One or more consumers subscribe to a channel

Kafka

Advanced features are available , colony 、 Load balancing 、 Dynamic capacity 、 Data backup, etc

　　 So to speak , If it works Kafka Just use Kafka, General scenarios that are not sensitive to data can also be applied Redis Of .