Redis in NoSQL database (4): redis publishing and subscription

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 .

Redis Publish and subscribe to

1、 Clients can subscribe to channels , Here's the picture ：

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

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