Why can multiversioning cause problems when performing transactions with the Read Uncommitted isolation level?

Multiversion Concurrency Control (MVCC) allows a database to store multiple versions of data to ensure consistency during concurrent transactions. At the Read Uncommitted isolation level, transactions can read data that has not yet been committed.

The problem arises when a transaction reads 'dirty' data — versions that may be rolled back. MVCC typically prevents reading such data, but this restriction is lifted at Read Uncommitted, which can lead to:

• Reading inconsistent or temporary data
• Loss of consistency during operations

Thus, using MVCC together with Read Uncommitted can create challenges in ensuring data correctness, as MVCC mechanisms are designed for stricter isolation levels.