UNSUBSCRIBE behavior in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the UNSUBSCRIBE command do in Redis?

It stops the client from receiving messages from the specified channels or all channels if none are specified.

beginner

If a client is subscribed to multiple channels, what happens when it sends UNSUBSCRIBE without any channel names?

The client unsubscribes from all channels it is currently subscribed to.

intermediate

What message does Redis send back to the client after an UNSUBSCRIBE command?

Redis sends a message showing the channel unsubscribed from and the number of channels the client is still subscribed to.

intermediate

Can a client unsubscribe from channels it is not subscribed to using UNSUBSCRIBE?

No, Redis ignores unsubscribe requests for channels the client is not subscribed to and does not send an error.

beginner

What happens if a client unsubscribes from all channels and has no subscriptions left?

The client stops receiving any published messages until it subscribes again.

What does the Redis UNSUBSCRIBE command do?

A Stops receiving messages from specified channels

B Deletes the channels permanently

C Publishes a message to all subscribers

D Creates new channels

UNSUBSCRIBE stops the client from receiving messages from the specified channels.

If you call UNSUBSCRIBE with no arguments, what happens?

A Subscribes to all channels

B Returns an error

C Unsubscribes from all channels

D Does nothing

Calling UNSUBSCRIBE without arguments unsubscribes the client from all channels.

What does Redis send back after an UNSUBSCRIBE command?

A A confirmation with the total number of channels in Redis

B A message with the channel name and remaining subscriptions count

C An error message

D No response

Redis replies with the channel unsubscribed from and how many subscriptions remain.

Can you unsubscribe from a channel you are not subscribed to?

A No, Redis ignores it silently

B Yes, and it returns an error

C Yes, and it unsubscribes anyway

D No, and it disconnects the client

Redis ignores unsubscribe requests for channels the client is not subscribed to without error.

What happens after a client unsubscribes from all channels?

A It receives messages from all channels

B It automatically subscribes to a default channel

C It disconnects from the server

D It stops receiving published messages

After unsubscribing from all channels, the client stops receiving published messages.

Explain how the UNSUBSCRIBE command works in Redis Pub/Sub.

Think about what happens when you want to stop listening to messages.

Describe the client state after unsubscribing from all channels in Redis.

Consider what it means to stop listening completely.