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Data & Analytics · Advanced

Multiversion Concurrency Control (MVCC)

A concurrency method that keeps multiple versions of rows so readers see a consistent snapshot without blocking writers.

Definition

MVCC underlies PostgreSQL, Oracle, MySQL InnoDB, SQL Server snapshot modes and lakehouse table formats. Old versions must be cleaned up, for example by VACUUM in PostgreSQL or Delta Lake.

Exam tip

'Readers don't block writers and writers don't block readers' describes MVCC.

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