Concurrency control and recovery in database systems
Concurrency control and recovery in database systems
Mobile wireless computing: challenges in data management
Communications of the ACM
Data broadcasting strategies over multiple unreliable wireless channels
CIKM '95 Proceedings of the fourth international conference on Information and knowledge management
Broadcast disks: data management for asymmetric communication environments
SIGMOD '95 Proceedings of the 1995 ACM SIGMOD international conference on Management of data
Balancing push and pull for data broadcast
SIGMOD '97 Proceedings of the 1997 ACM SIGMOD international conference on Management of data
“Data in your face”: push technology in perspective
SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
Efficient concurrency control for broadcast environments
SIGMOD '99 Proceedings of the 1999 ACM SIGMOD international conference on Management of data
Updating and Querying Databases that Track Mobile Units
Distributed and Parallel Databases - Special issue on mobile data management and applications
Adaptive Broadcast Protocols to Support Power Conservant Retrieval by Mobile Users
ICDE '97 Proceedings of the Thirteenth International Conference on Data Engineering
Exploiting Versions for Handling Updates in Broadcast Disks
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
Supporting Read-Only Transactions in Wireless Broadcasting
DEXA '98 Proceedings of the 9th International Workshop on Database and Expert Systems Applications
Broadcast on Demand: Efficient and Timely Dissemination of Data in Mobile Environments
RTAS '97 Proceedings of the 3rd IEEE Real-Time Technology and Applications Symposium (RTAS '97)
Maintaining Temporal Coherency of Virtual Data Warehouses
RTSS '98 Proceedings of the IEEE Real-Time Systems Symposium
Maintaining consistency of data in mobile distributed environments
ICDCS '95 Proceedings of the 15th International Conference on Distributed Computing Systems
Efficient Algorithms for Scheduling Single and Multiple Channel Data Broadcast
Efficient Algorithms for Scheduling Single and Multiple Channel Data Broadcast
Efficient Dissemination of Transaction-Consistent Data in Broadcast Environments
IEEE Transactions on Knowledge and Data Engineering
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Although data broadcast has been shown to be an efficient method for disseminating data items in mobile computing systems, the issue on how to ensure consistency and currency of data items provided to mobile transactions (MT), which are generated by mobile clients, has not been examined adequately. While data items are being broadcast, update transactions may install new values for them. If the executions of update transactions and the broadcast of data items are interleaved without any control, mobile transactions may observe inconsistent data values. The problem will be more complex if the mobile clients maintain some cached data items for their mobile transactions. In this paper, we propose a concurrency control method, called ordered update first with order (OUFO), for the mobile computing systems where a mobile transaction consists of a sequence of read operations and each MT is associated with a time constraint on its completion time. Besides ensuring data consistency and maximizing currency of data to mobile transactions, OUFO also aims at reducing data access delay of mobile transactions using client caches. A hybrid re-broadcast/invalidation report (IR) mechanism is designed in OUFO for checking the validity of cached data items so as to improve cache consistency and minimize the overhead of transaction restarts due to data conflicts. This is highly important to the performance of the mobile computing systems where the mobile transactions are associated with a deadline constraint on their completion times. Extensive simulation experiments have been performed to compare the performance of OUFO with two other efficient schemes, the multi-version broadcast method and the periodic IR method. The performance results show that OUFO offers better performance in most aspects, even when network disconnection is common.