Redis publishing and subscription

1. What is publish and subscribe

Redis Publish subscribe (pub/sub) It's a message communication mode ： sender (pub) Send a message , subscriber (sub) receive messages . Redis Clients can subscribe to any number of channels .

2. Redis Publish and subscribe to

1、 The client can subscribe to channels, as shown in the figure below
A client can subscribe to multiple channels .

2、 When you post a message to this channel , The message is sent to the subscribing client

3. Publish and subscribe command line implementation
1、 Open a client subscription channel1

SUBSCRIBE channel1

2、 Open another client , to channel1 Release the news hello

publish channel1 hello

Back to 1 Is the number of subscribers

3、 Open the first client to see the sent message

notes ：

Published messages are not persistent , If the subscription client does not receive hello, Only messages published after subscription can be received