Serializable Snapshot Isolation: True Serializability Without Heavy Locking
SSI upgrades Snapshot Isolation to true serializability. It optimistically lets transactions run, but aborts one if a dangerous read-write dependency arises. This prevents subtle data corruption in systems like PostgreSQL without heavy locking.
Serializable Snapshot Isolation (SSI) provides true serializability by upgrading standard Snapshot Isolation. It optimistically allows transactions to work on a consistent data snapshot, but tracks read-write dependencies to detect "write skew" anomalies that SI alone misses. If a dangerous dependency cycle forms, it aborts one transaction to maintain correctness. It's used in databases like PostgreSQL for the strongest guarantee without the high cost of two-phase locking. The footgun: your application must handle and retry transaction aborts.
Read the original → Wikipedia: Serializable Snapshot Isolation
- #databases
- #transactions
- #acid
- #isolation
- #concurrency
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