Semantic serializability: A correctness criterion for processing transactions in advanced database applications

A self-adaptable scheduler for synchronizing transactions in dynamically configurable environments

“…The trapezoidal shape was chosen for these fuzzy sets because this shape has good response time (linear function) and its configuration is easy. With this shape, the specialist defines the values he is certain of: interval [0, x 1 ] where the variable presents a low value, the interval [x 2 , x 3 ] where it presents a medium value and the high value interval [x 4 , 100]. The intervals in which the specialist is uncertain about behavior variations are represented by [x 1 , x 2 ] and [x 3 , x 4 ].…”

“…This Section presents how ITS produces correct schedules, even during the transition phase and another important featureit's ability to implement two different correctness criteria: syntactic serializability (classical correctness criterion) and semantic serializability [4].…”

“…The S e S model is based on the use of semantic knowledge to relax the notion of absolute transaction atomicity [4]. The key idea of that transaction model is to ''see" an MDBC as a collection of disjoint sets of objects, each of which represents a single mobile database.…”

“…With this approach a transaction may consist of several atomic units. An atomic unit (Definition 9) is the set of operations of the transaction over a semantic unit [4]. In the S e S transaction model, a schedule S is correct iff S is semantically serializable.…”

“…SUa T j , where T i , T j 2 N, and there are two operations, which are in conflict, p 2 OP(T i ), q 2 OP(T j ), p < S q, on an object of the SU a . In [4], some concurrency control protocols with exclusive aggressive or conservative behavior based on S e S correctness criterion are presented and the S e S model is discussed more thoroughly.…”