一种嵌入式移动实Petri的并发控制策略.pdfVIP

36 2 Vol. 36 No. 2 2009 2 Computer Science F eb. 2009 ( 华中科技大学计算机学院 武汉430074) , ( OCC2 AST OSR) , , , , , , , , , Concurrency Contr ol St rategy of Embedded Mob ile Real2time Datab ase WU H ai CHEN Wei LU Yan2 sheng ( Comput er Col lege, H uazhong U niver sity of Scien ce and T echnology, Wuhan 430074, Ch ina) Abstr act Besides maintaining t he characterist ics of t raditional tran sact ion s, the embedded mobile r eal2time tr ansactions should focu s on how to resolve the pr oblem of prior ity r eversing, fr uitless restarting, and consistency of global data and high p erformance of the mixed tran sact ion s sy stem. Optimist ic Concurrency Control with Ab solute Ser ialize Time Order and Selected Restart ( OCC2 ASTOSR) u ses an absolute t imest amp to adju st the serialize order of tran saction s in mobile client and cent ral ser ver, check s over the confliction of data access and takes the select ed r estart method to resolve the conf liction . Tr ansactions update their read set and writ e set when access the data and every dat a maintain s some rela2 t ional time information, they exchange message via wireless networ k and complete two phase validat ion in the cont rol of the whole sy stem. Keyword s Real2time tr ansactions, Optimistic concurr ency contr ol, Ab solute seria lize time order , Selected restar t OCC2AST OSR ( OCC with Absolute Ser ialize Time Order 1 and Select ed Restar t) , ,