What is the difference between causal consistency and strong consistency?

What is the difference between causal consistency and strong consistency?

Causal consistency ensures that operations that are causally related are seen by all nodes in the same order, while strong consistency guarantees that all operations appear to happen instantaneously at some point in time.

Can you give an example of each?

Sure! In causal consistency, if one user sends a message and another replies, all users will see the reply after the message. In strong consistency, if a user updates a value, all users will see that update immediately.

Which one is better for real-time applications?

It depends on the application. Strong consistency is better for applications requiring immediate accuracy, while causal consistency can be more efficient for collaborative applications where some delay is acceptable.

What are the trade-offs between the two?

The trade-offs include performance and complexity. Strong consistency can lead to higher latency and lower availability, while causal consistency may allow for better performance but can complicate the reasoning about the order of operations.