11.5 Timestamping
An alternate concurrency control mechanism that eliminates the deadlock problem is timestamping. In this scheme, no locks are used, so no deadlocks can occur. A timestamp for a transaction is a unique identifier that indicates the relative starting time of the transaction. It could be the reading on the system clock at the time the transaction started, or it could be the value of a logical counter that is incremented every time a new transaction starts. In either case, the timestamp value of each transaction T, which we will indicate by TS(T), is unique and indicates how old the transaction is. The effect of timestamping is to assign a serial order to the transactions. The protocol then ensures that the order is met, by not ...
Get Databases Illuminated, 4th Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
