Which statement describes Read-Your-Own-Writes consistency?

Which statement describes Read-Your-Own-Writes consistency?

• A. All users always see updates immediately once written.
• B. A model where a user always sees their own updates immediately, while others may see older versions.
• C. A model that prevents any user from seeing their own updates until replication completes.
• D. A model that ensures global ordering of all operations.

Answer: (B)

Read-Your-Own-Writes means that once you write data, you are guaranteed to see your own write reflected in your future reads. It focuses on the perspective of the originating client: the writer should observe their changes immediately, even if other clients continue to see old versions until their see-propagation catches up. This provides a predictable editing experience for the user without forcing all clients to observe the write at the same time. The described model fits this idea: a user always sees their own updates immediately, while others may see older versions. It captures the essence that personal visibility is instant, but global visibility across all clients is not guaranteed right away. Why the other ideas don’t fit: asking everyone to see updates immediately is stronger than Read-Your-Own-Writes (it implies global, immediate consistency). Requiring no one to see their own updates until replication completes would violate the fundamental guarantee of RYOW. Demanding global ordering of all operations is about a stricter form of consistency (like linearizability) and isn’t what RYOW specifically requires.

Read-Your-Own-Writes means that once you write data, you are guaranteed to see your own write reflected in your future reads. It focuses on the perspective of the originating client: the writer should observe their changes immediately, even if other clients continue to see old versions until their see-propagation catches up. This provides a predictable editing experience for the user without forcing all clients to observe the write at the same time.

The described model fits this idea: a user always sees their own updates immediately, while others may see older versions. It captures the essence that personal visibility is instant, but global visibility across all clients is not guaranteed right away.

Why the other ideas don’t fit: asking everyone to see updates immediately is stronger than Read-Your-Own-Writes (it implies global, immediate consistency). Requiring no one to see their own updates until replication completes would violate the fundamental guarantee of RYOW. Demanding global ordering of all operations is about a stricter form of consistency (like linearizability) and isn’t what RYOW specifically requires.