Scheduling transactions with temporal constraints: exploiting data semantics

IEEE Transactions on Knowledge and Data Engineering - Tập 14 Số 5 - Trang 1155-1166 - 2002
Ming Xiong1, K. Ramamritham2, J.A. Stankovic3, D. Towsley4, R. Sivasankaran5
1Bell Laboratories, Murray Hill, NJ, USA
2Indian Institute of Technology, Bombay, India
3The Department of Computer Science, University of Virginia, Charlottesville, VA, USA
4The Department of Computer Science, University of Massachusetts, Amherst, MA, USA
5Knumi, Inc., Cambridge, MA, USA

Tóm tắt

In this paper, issues involved in the design of a real-time database which maintains data temporal consistency are discussed. The concept of data-deadline is introduced and time cognizant transaction scheduling policies are proposed. Informally, data-deadline is a deadline assigned to a transaction due to the temporal constraints of the data accessed by the transaction. Further, two time cognizant forced wait policies which improve performance significantly by forcing a transaction to delay further execution until a new version of sensor data becomes available are proposed. A way to exploit temporal data similarity to improve performance is also proposed. Finally, these policies are evaluated through detailed simulation experiments. The simulation results show that taking advantage of temporal data semantics in transaction scheduling can significantly improve the performance of user transactions in realtime database systems. In particular, it is demonstrated that under the forced wait policy, the performance can be improved significantly. Further improvements result by exploiting data similarity.

Từ khóa

#Time factors #Database systems #Transaction databases #Real time systems #Protocols #Scheduling #Delay effects #Process design #Robot sensing systems #Navigation

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