Transactions & Isolation Lessons

MVCC internals: how databases store row version chains, how a snapshot decides which version it sees, and why one long-running transaction causes table bloat and vacuum pressure.

Serializable Snapshot Isolation (SSI) explained: how a database keeps non-blocking snapshot reads yet stays serializable by tracking rw-dependencies and aborting dangerous write skew.

Transaction isolation levels explained: read committed, repeatable read, snapshot, serializable — and the anomalies (dirty reads, write skew, phantoms) each one allows or prevents.