Backend & systems·Consistency and replication
the user updates their profile, the page reloads from a replica, and their change is missing for two seconds.
Read-your-writes consistency
Also calledread your own writes, session consistency
A guarantee that a client always sees its own prior writes, even under eventual consistency elsewhere. It is usually implemented by routing that user's reads to the leader for a short window, or by tracking a write timestamp and waiting for a replica to catch up. Skipping it is the single most common source of "the save button doesn't work" bug reports.