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Data & Analytics · Advanced

Repeatable Read

An isolation level that guarantees rows read once will return the same values if read again in the same transaction.

Definition

Repeatable Read holds shared locks on read rows until the transaction ends, or uses snapshots in MySQL InnoDB. It prevents dirty and non-repeatable reads, but under the ANSI definition phantoms are still possible.

Exam tip

Repeatable Read still allows phantoms; only Serializable prevents them under the ANSI definition.

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