Answer
MVCC allows multiple transactions to read and write data without blocking. Readers view snapshot data while writers update the latest version using undo logs.
Quick Answer
MySQL InnoDB MVCC: each row has two hidden columns - DB_TRX_ID (transaction that last modified it) and DB_ROLL_PTR (pointer to undo log for old versions). When a transaction reads a row, it uses a read view (snapshot of active transactions at read start) to determine which row version is visible. Older versions are stored in the undo log and accessed via the rollback pointer chain.
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SugharaIQ Editorial Team
Verified Answer
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Source: SugharaIQ