Multidimensional timestamp protocols for concurrency control

We propose multidimensional timestamp protocols where each transaction has a timestamp vector of multiple elements. The timestamp vectors need not be distinct but do define a partial order. The serializability order among the transactions is determined by any topological sort of their timestamp vectors. The timestamp in our protocols is constructed dynamically, not just based on the starting/finishing time as in conservative and optimistic timestamp methods, and thus the concurrency control can be enforced based on more precise dependency information derived from the operations of the transactions. Several classes of logs have been identified based on the degree of concurrency which represents the number of logs accepted by a concurrency controller [12]. The class for our protocols is different from any previously known classes such as two phase locking (2PL), D-serializable (DSR), strictly serializable (SSR), timestamp ordering (TO), which have been defined in [5, 9, 12, 13]. If the dimension of the timestamp vector is one, then our protocols recognize the class timestamp ordering (TO). We will briefly discuss the implementation of the concurrency control algorithm for the new class.