Scheduling Real-Time Nested Transactions in Mobile Broadcast Environments

This paper presents MVOCC-NT protocol for processing mobile real-time nested transaction in mobile broadcast environments. The protocol can eliminate conflicts between mobile read-only and mobile update nested transactions, and resolve data conflicts flexibly using multiversion dynamic adjustment of serialization order to avoid unnecessary restarts of transactions. Transaction validation is performed at two phases: pre-validation and final validation. At the MHs, all mobile transactions perform pre-validation of transactions. At MHs transactions that survive in pre-validation must be submitted to the server for final validation. Such an early data conflict detect detection feature can save processing and communication resources. For a ready-only nested transaction at the MH, it can be committed locally if it passes all the pre-validation in the course of it execution. The simulation results show that the new concurrency control protocol proposed offers better performance than other protocols.