Module Assessment

1.

What is the key difference between Redis pub/sub and Redis Streams for event messaging?

Pub/sub delivers messages to active subscribers only, while Streams persist messages for consumer groups to process at their own pace

Pub/sub can handle more messages per second than Streams

Streams are only for string data while pub/sub works with any data type

2.

When building a processing pipeline with multiple services that need automatic retry on failure, which pattern should you use?

Redis Streams with consumer groups for reliable task coordination and built-in retry handling

Redis pub/sub for real-time distribution of work items

A simple Redis List with LPUSH and RPOP

3.

Which Redis command is used to add a new message to a Stream?

XADD

LPUSH

PUBLISH

4.

Which scenario is best suited for Redis pub/sub messaging?

Broadcasting real-time status updates to multiple connected clients or services that are currently listening

Storing messages that arrive when subscribers are offline and delivering them when subscribers reconnect

Implementing a reliable work queue where tasks must be processed exactly once

5.

How would you coordinate multiple AI workers processing documents from a Stream to ensure no document is processed by more than one worker simultaneously?

Use XREADGROUP to pull tasks from a consumer group, which automatically assigns unacknowledged tasks to different workers

Use XREAD to have each worker independently read from the Stream without coordination

Use pub/sub channels with one channel per worker

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