Backend & systems·Transactions and isolation
the database promises the result is as if the concurrent transactions had run one after another, and aborts one of them to keep that promise.
Serialisable
Also calledserializable isolation
The strongest isolation level: the outcome is equivalent to some serial order of the transactions. It eliminates every anomaly, including write skew, which is why it is the correct answer for financial invariants. The cost is aborts under contention, so every transaction needs a retry loop, and throughput drops on hot rows.