A REAL-TIME CONCURRENCY-CONTROL PROTOCOL FOR MAIN-MEMORY DATABASE-SYSTEMS

Protocols developed so far for concurrency control in real-time databa se systems have assumed a dynamic acquisition of data resources as it is impossible to predict which instances of relations will actually be accessed by each transaction. In this paper double dagger, we present a new concurrency control protocol for main-memory real-time database systems, which is based on predeclaration of data requirements at a r elation granularity. When a transaction is submitted, it is possible t o detect with simple syntactical means which relations will be accesse d by the transaction. Preacquisition of data resources enables the sys tem to execute transactions in a conflict-free manner. The protocol al so offers the possibility of determining execution times without the e ffects of blocking and I/O, thereby allowing us to give guarantees for the execution of high-priority transactions. Through a series of simu lation experiments, the protocol is compared against some typical conc urrency control protocols proposed recently for real-time database sys tems. (C) 1998 Elsevier Science Ltd. All rights reserved.