Gestion de la surcharge dans les systèmes de gestion de base de données temps réel

We propose a transaction management protocol for increasing concurrency and deadline satisfaction in a real-time distributed database. This protocol combines the concepts of data imprecision and transaction importance. The isolation level tolerated is not maximal, that is, each read transaction may access a data item while another transaction is writing it provided that the amount of inconsistency introduced by the latter does not exceed the epsilon threshold. When an overload occurs, the transactions with the lowest importance values are aborted. We have developed a simulation platform to evaluate the performance of the protocol. MOTS-CLÉS : système temps réel, ordonnancement temps réel, système de gestion de bases de données temps réel, surcharge temporelle, importance, données imprécises, moniteur transactionnel.