Freezing as a correctness measure for Multiversion Timestamp Ordering protocol

Concurrency control techniques are required for transaction scheduling in order to maintain consistency of data. This paper analyses the correctness of Multiversion Concurrency Control (MVCC) algorithm, namely Multiversion Timestamp Ordering, supplemented with freezing technique. Freezing incorporates F-serial, which is more general than 1-serial. It allows the transactions to read older versions which is not possible in 1-serial schedules. Using freezing, MVCC algorithms can prevent the unnecessary delay or aborts of the conflicting transactions, which is desirable in real-time database systems, where the timing constraint has to be met. MVTO Algorithm used here makes use of a specialized version of Serialisation Graph, Called MultiVersion Serialisation Graph (MVSG) to resolve data conflicts to maintain the serialization order among conflicting transactions.