Consider a read of data item X by transaction T i . Since no transaction ever waits, no deadlocks. Thomas' Write Rule Simple modification to the timestamp protocol. Consider the second case of the write protocol. Instead of rejecting, simply ignore the new write and continue.
Every transaction consists of three phases.
Timestamp ordering is by the Validation timestamp. Multiversion Timestamp Ordering Each transaction has a timestamp. Each datum consists of a set of data. Locking Consider read-only transactions separately from update transactions. For update transactions, use rigorous two-phase locking.