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 nodes see operations in the exact same order, regardless of causality.

Can you give an example of each?

Sure! In causal consistency, if one user posts a comment and another replies, all users will see the reply after the comment. In strong consistency, if a user updates their profile, everyone sees the updated profile immediately, even if they were offline.

Which one is better for real-time applications?

It depends on the application. Causal consistency is often better for collaborative applications where the order of actions matters, while strong consistency is crucial for applications requiring strict data accuracy, like banking.

What are the trade-offs between the two?

Causal consistency allows for higher availability and lower latency but can lead to confusion in the order of operations. Strong consistency provides clarity and accuracy but can introduce latency and reduce availability.