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eventual consistency
If writes stop, copies agree. Until then they may disagree. The UI has to admit that.
What is eventual consistency?
Eventual consistency means replicas converge without a promise about when. Strong consistency means a read sees the latest acknowledged write. “Eventual” is a product behavior: the like count, the search index, the other phone.
Why does eventual consistency matter when vibe coding?
Models store denormalized counts and read them as truth. Two taps race and the number is wrong forever, not just briefly. Say what is allowed to be stale and what converges.
How do you do eventual consistency?
Mark each read model: stale-ok or not. Stale-ok gets a replica or a projection. Not-stale stays on the primary and a transaction. Do not mix them in one sentence.
How do you ask a model for eventual consistency?
(View) is eventually consistent. Stale reads are allowed for (seconds). (Balance or permission) is not. Do not read the projection to authorize a write.
What goes wrong with eventual consistency?
Using “eventual” as an excuse for a bug that never converges. If writes have stopped and it is still wrong, that is a broken projection, not CAP.