Hybrid concurrency control for mobile computing

Proposes a hybrid concurrency control scheme which can alleviate the effects of frequent disconnections and bandwidth limitations in mobile computing environments. If a transaction in a mobile host executes only read operations, our concurrency control scheme is the same as the optimistic concurrency control scheme based on the timestamp history. Otherwise, if it executes write operations, the write set has to be sent to a fixed host during the execution phase. If a disconnection from the mobile host occurs, the fixed host performs a pre-validation of the write set. As a result of this pre-validation, if conflicts are detected, the transaction is aborted. Otherwise, we use the locking method called “weak lock”. Our scheme reduces the number of aborts and the validation time without message overheads