Eventual Consistency
ELI5 — The Vibe Check
Eventual consistency means 'give it a moment and everything will match up.' You write data to one server, and the other servers will get the update... eventually. Like posting on social media: some friends see it immediately, others see it 30 seconds later. Everyone gets there, just not at the same time.
Real Talk
Eventual consistency is a consistency model where, given no new updates, all replicas will eventually converge to the same state. It allows replicas to temporarily diverge for higher availability and lower latency. The convergence window depends on replication lag, network conditions, and conflict resolution strategies. Common in AP systems like DynamoDB and Cassandra.
When You'll Hear This
"Eventual consistency means your read might be slightly stale, but the system stays available." / "Social media feeds are eventually consistent and nobody cares."
Related Terms
CAP Theorem
The CAP theorem says a distributed database can only guarantee two out of three things: Consistency (everyone sees the same data), Availability (every requ...
Conflict Resolution
Conflict resolution is what happens when two database servers both change the same thing at the same time and then try to sync up.
Read Replica
A read replica is a copy of your database that only handles read queries.
Strong Consistency
Strong consistency means the moment you write something, everyone everywhere immediately sees the updated value. No 'give it a sec' nonsense.