Redis learning notes pipeline

Redis The client execution of a command is divided into the following four processes

No matter how long the network delays , Packets can always reach the server from the client , And return data from the server to the client , Such from 1~4 The time required is called Round Trip Time（RTT, Round trip time ）

Redis Batch operation commands are provided （ for example mget、mset etc. ）, Save effectively RTT, But most commands do not support batch operations , It is very unwise to consume time on the network every time you request ,Pipeline（ Assembly line ） The mechanism can improve the above problems , It can combine a group of Redis Command assembly , Through a RTT Transferred to the Redis, Will this group again Redis The execution of the command is returned to the client in order

The picture below is not used Pipeline The situation of , There will be as many requests as there are RTT, It will spend a lot of time on network transmission

Pipeline Execution speed is generally faster than item by item execution ; The greater the network delay between the client and the server ,Pipeline The more obvious the effect of , The figure below shows the use of pipeline Implementation

have access to Pipeline Simulate the effect of batch operation , But when using it, you should pay attention to the difference between it and the native batch command , It includes the following points ：

• The native batch command is atomic ,Pipeline It's non atomic
• A native batch command is a command that corresponds to multiple key,Pipeline Supports multiple commands
• The native batch command is Redis The server supports the implementation of , and Pipeline It needs to be realized by both the server and the client

Pipeline Although easy to use , But every time Pipeline The number of assembly commands cannot be unlimited , Otherwise, one assembly Pipeline Too much data , On the one hand, it will increase the waiting time of the client , On the other hand, it will cause some network congestion , It's possible to put a Pipeline Split into several smaller Pipeline To complete .Pipeline Only one can be operated Redis example , But even in distributed Redis Scene , It can also be used as an important optimization method for batch operation