Transaction processing in mobile real-time database systems

Multiversion optimistic concurrency control protocol (MVOCC) is presented for processing mobile real-time transactions. The protocol can eliminate conflicts between read-only and update transactions and resolve data conflicts flexibly using dynamic adjustment of serialization order to avoid unnecessary restarts of transactions. The Mobile hosts (MHs) do not need to synchronize with each other and server for data conflict detection. Read-only transactions can be efficiently processed at MHs. Response time of read-only transactions is greatly improved. Local validation of transactions is performed at MHs. To prevent cached data inconsistent transactions that survive in local validation must be submitted to server for global validation. The protocol presented is compared with OCC-TI-WAIT50 and HP2PL by simulation experiments. The results of experiment show that the protocol performs better than other protocols under normal load.